1
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Znati S, Wharwood J, Tezanos KG, Li X, Mohseni PK. Metal-assisted chemical etching beyond Si: applications to III-V compounds and wide-bandgap semiconductors. NANOSCALE 2024; 16:10901-10946. [PMID: 38804075 DOI: 10.1039/d4nr00857j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Metal-assisted chemical etching (MacEtch) has emerged as a versatile technique for fabricating a variety of semiconductor nanostructures. Since early investigations in 2000, research in this field has provided a deeper understanding of the underlying mechanisms of catalytic etching processes and enabled high control over etching conditions for diverse applications. In this Review, we present an overview of recent developments in the application of MacEtch to nanomanufacturing and processing of III-V based semiconductor materials and other materials beyond Si. We highlight the key findings and developments in MacEtch as applied to GaAs, GaN, InP, GaP, InGaAs, AlGaAs, InGaN, InGaP, SiC, β-Ga2O3, and Ge material systems. We further review a series of active and passive devices enabled by MacEtch, including light-emitting diodes (LEDs), field-effect transistors (FETs), optical gratings, sensors, capacitors, photodiodes, and solar cells. By reviewing demonstrated control of morphology, optimization of etch conditions, and catalyst-material combinations, we aim to distill the current understanding of beyond-Si MacEtch mechanisms and to provide a bank of reference recipes to stimulate progress in the field.
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Affiliation(s)
- Sami Znati
- Microsystem Engineering, Rochester Institute of Technology, Rochester, NY 16423, USA.
- NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Juwon Wharwood
- NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, NY 14623, USA
- Department of Electrical and Computer Engineering, Howard University, Washington, DC 20059, USA
| | - Kyle G Tezanos
- NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, NY 14623, USA
- School of Materials Science and Chemistry, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Xiuling Li
- Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin, Austin, TX 78758, USA
| | - Parsian K Mohseni
- Microsystem Engineering, Rochester Institute of Technology, Rochester, NY 16423, USA.
- NanoPower Research Laboratories, Rochester Institute of Technology, Rochester, NY 14623, USA
- School of Materials Science and Chemistry, Rochester Institute of Technology, Rochester, NY 14623, USA
- Department of Electrical and Microelectronic Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
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2
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Kim K, Choi S, Bong H, Lee H, Kim M, Oh J. Catalytic nickel silicide as an alternative to noble metals in metal-assisted chemical etching of silicon. NANOSCALE 2023; 15:13685-13691. [PMID: 37555310 DOI: 10.1039/d3nr02053c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Metal-assisted chemical etching (MACE) has received much attention from researchers because it can be used to fabricate plasma-free anisotropic etching profiles for semiconductors. However, the etching mechanism of MACE is based on the catalytic reaction of noble metals, which restricts its use in complementary metal oxide semiconductor (CMOS) processes. To obtain process compatibility, we developed catalytic Ni after alloying it with Si as a substitute for noble metals in the MACE of Si substrates. Nickel silicide is a material commonly used as a contact electrode in CMOS processes. When NiSi was used as the catalyst, the anisotropic etching of Si with a smooth surface was successfully demonstrated. Silicidation increased the standard reduction potential of the Ni alloy and enhanced the electrochemical stability in the MACE of Si. In contrast, when pure Ni was used as the catalyst, a rough-etched surface was fabricated because of the low standard reduction potential. Based on the experimental results, the factors affecting the MACE of Si were systematically analyzed to optimize the catalytic NiSi properties. The implementation of the NiSi alloy potentially eliminates the use of noble metals in MACE and allows the technology to be adopted in contemporary CMOS processes.
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Affiliation(s)
- Kyunghwan Kim
- School of Integrated Technology, Yonsei University, 85, Songdogwahak-ro, Yeonsu-gu, Incheon, 21983, Republic of Korea.
| | - Sunhae Choi
- School of Integrated Technology, Yonsei University, 85, Songdogwahak-ro, Yeonsu-gu, Incheon, 21983, Republic of Korea.
| | - Haekyun Bong
- School of Integrated Technology, Yonsei University, 85, Songdogwahak-ro, Yeonsu-gu, Incheon, 21983, Republic of Korea.
| | - Hanglim Lee
- SEMES, 1339, Hyohaeng-ro, Hwaseong-Si, Gyeonggi-do, 18383, Republic of Korea
| | - Minyoung Kim
- SEMES, 1339, Hyohaeng-ro, Hwaseong-Si, Gyeonggi-do, 18383, Republic of Korea
| | - Jungwoo Oh
- School of Integrated Technology, Yonsei University, 85, Songdogwahak-ro, Yeonsu-gu, Incheon, 21983, Republic of Korea.
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3
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Lin YC, Lo I, Tsai CD, Wang YC, Huang HC, Li CA, Chou MMC, Chang TC. Optimization of Ternary In xGa 1-xN Quantum Wells on GaN Microdisks for Full-Color GaN Micro-LEDs. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1922. [PMID: 37446439 DOI: 10.3390/nano13131922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/20/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023]
Abstract
Red, green, and blue light InxGa1-xN multiple quantum wells have been grown on GaN/γ-LiAlO2 microdisk substrates by plasma-assisted molecular beam epitaxy. We established a mechanism to optimize the self-assembly growth with ball-stick model for InxGa1-xN multiple quantum well microdisks by bottom-up nanotechnology. We showed that three different red, green, and blue lighting micro-LEDs can be made of one single material (InxGa1-xN) solely by tuning the indium content. We also demonstrated that one can fabricate a beautiful InxGa1-xN-QW microdisk by choosing an appropriate buffer layer for optoelectronic applications.
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Affiliation(s)
- Yu-Chung Lin
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Ikai Lo
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Cheng-Da Tsai
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Ying-Chieh Wang
- Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Hui-Chun Huang
- Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Chu-An Li
- Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Mitch M C Chou
- Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Ting-Chang Chang
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
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4
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Li X, Zhang J, Yue C, Tang X, Gao Z, Jiang Y, Du C, Deng Z, Jia H, Wang W, Chen H. High performance visible-SWIR flexible photodetector based on large-area InGaAs/InP PIN structure. Sci Rep 2022; 12:7681. [PMID: 35538226 PMCID: PMC9090829 DOI: 10.1038/s41598-022-11946-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 05/03/2022] [Indexed: 11/11/2022] Open
Abstract
Mechanically flexible optoelectronic devices and systems can enable a much broader range of applications than what their rigid counterparts can do, especially for novel bio-integrated optoelectronic systems, flexible consumer electronics and wearable sensors. Inorganic semiconductor could be a good candidate for the flexible PD when it can keep its high performance under the bending condition. Here, we demonstrate a III–V material-based flexible photodetector operating wavelength from 640 to 1700 nm with the high detectivity of 5.18 × 1011 cm‧Hz1/2/W and fast response speed @1550 nm by using a simply top-to-down fabrication process. The optoelectrical performances are stable as the PDs are exposed to bending cycles with a radius of 15 mm up to 1000 times. Furthermore, the mechanical failure mode of the PD is also investigated, which suggests that the cracking and delamination failure mode are dominant in bending up and bending down direction, respectively. Such a flexible III–V material-based PD and design with stable and high performance could be a promising strategy for the application of the flexible broad spectrum detection.
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Affiliation(s)
- Xuanzhang Li
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Junyang Zhang
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chen Yue
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiansheng Tang
- Laser Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250014, China
| | - Zhendong Gao
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Jiang
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,Center of Materials and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chunhua Du
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,Center of Materials and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.,The Yangtze River Delta Physics Research Center, Liyang, 213000, China
| | - Zhen Deng
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China. .,Center of Materials and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China. .,The Yangtze River Delta Physics Research Center, Liyang, 213000, China.
| | - Haiqiang Jia
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,Center of Materials and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.,Songshan Lake Materials Laboratory, Dongguan, 523808, China
| | - Wenxin Wang
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,Center of Materials and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.,Songshan Lake Materials Laboratory, Dongguan, 523808, China
| | - Hong Chen
- Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.,Center of Materials and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China.,The Yangtze River Delta Physics Research Center, Liyang, 213000, China.,Songshan Lake Materials Laboratory, Dongguan, 523808, China
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5
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Wang Q, Zhou K, Zhao S, Yang W, Zhang H, Yan W, Huang Y, Yuan G. Metal-Assisted Chemical Etching for Anisotropic Deep Trenching of GaN Array. NANOMATERIALS 2021; 11:nano11123179. [PMID: 34947528 PMCID: PMC8704282 DOI: 10.3390/nano11123179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/20/2021] [Accepted: 11/21/2021] [Indexed: 12/03/2022]
Abstract
Realizing the anisotropic deep trenching of GaN without surface damage is essential for the fabrication of GaN-based devices. However, traditional dry etching technologies introduce irreversible damage to GaN and degrade the performance of the device. In this paper, we demonstrate a damage-free, rapid metal-assisted chemical etching (MacEtch) method and perform an anisotropic, deep trenching of a GaN array. Regular GaN microarrays are fabricated based on the proposed method, in which CuSO4 and HF are adopted as etchants while ultraviolet light and Ni/Ag mask are applied to catalyze the etching process of GaN, reaching an etching rate of 100 nm/min. We comprehensively explore the etching mechanism by adopting three different patterns, comparing a Ni/Ag mask with a SiN mask, and adjusting the etchant proportion. Under the catalytic role of Ni/Ag, the GaN etching rate nearby the metal mask is much faster than that of other parts, which contributes to the formation of deep trenches. Furthermore, an optimized etchant is studied to restrain the disorder accumulation of excessive Cu particles and guarantee a continuous etching result. Notably, our work presents a novel low-cost MacEtch method to achieve GaN deep etching at room temperature, which may promote the evolution of GaN-based device fabrication.
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Affiliation(s)
- Qi Wang
- School of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China; (Q.W.); (K.Z.); (W.Y.); (H.Z.); (W.Y.)
| | - Kehong Zhou
- School of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China; (Q.W.); (K.Z.); (W.Y.); (H.Z.); (W.Y.)
| | - Shuai Zhao
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wen Yang
- School of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China; (Q.W.); (K.Z.); (W.Y.); (H.Z.); (W.Y.)
| | - Hongsheng Zhang
- School of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China; (Q.W.); (K.Z.); (W.Y.); (H.Z.); (W.Y.)
| | - Wensheng Yan
- School of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China; (Q.W.); (K.Z.); (W.Y.); (H.Z.); (W.Y.)
| | - Yi Huang
- School of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China; (Q.W.); (K.Z.); (W.Y.); (H.Z.); (W.Y.)
- Correspondence: (Y.H.); (G.Y.)
| | - Guodong Yuan
- State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China;
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Correspondence: (Y.H.); (G.Y.)
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6
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Mallavarapu A, Ajay P, Barrera C, Sreenivasan SV. Ruthenium-Assisted Chemical Etching of Silicon: Enabling CMOS-Compatible 3D Semiconductor Device Nanofabrication. ACS APPLIED MATERIALS & INTERFACES 2021; 13:1169-1177. [PMID: 33348977 DOI: 10.1021/acsami.0c17011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The semiconductor industry's transition to three-dimensional (3D) logic and memory devices has revealed the limitations of plasma etching in reliable creation of vertical high aspect ratio (HAR) nanostructures. Metal-assisted chemical etch (MacEtch) can create ultra-HAR, taper-free nanostructures in silicon, but the catalyst used for reliable MacEtch-gold-is not CMOS (complementary metal-oxide-semiconductor)-compatible and therefore cannot be used in the semiconductor industry. Here, for the first time, we report a ruthenium MacEtch process that is comparable in quality to gold MacEtch. We introduce new process variables-catalyst plasma pretreatment and surface area-to achieve this result. Ruthenium is particularly desirable as it is not only CMOS-compatible but has also been introduced in semiconductor fabrication as an interconnect material. The results presented here remove a significant barrier to adoption of MacEtch for scalable fabrication of 3D semiconductor devices, sensors, and biodevices that can benefit from production in CMOS foundries.
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Affiliation(s)
- Akhila Mallavarapu
- NASCENT Engineering Research Center, University of Texas at Austin, Austin, Texas 78758, United States
| | - Paras Ajay
- NASCENT Engineering Research Center, University of Texas at Austin, Austin, Texas 78758, United States
| | - Crystal Barrera
- NASCENT Engineering Research Center, University of Texas at Austin, Austin, Texas 78758, United States
| | - S V Sreenivasan
- NASCENT Engineering Research Center, University of Texas at Austin, Austin, Texas 78758, United States
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7
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Muzzillo CP, Wong E, Mansfield LM, Simon J, Ptak AJ. Patterning Metal Grids for GaAs Solar Cells with Cracked Film Lithography: Quantifying the Cost/Performance Tradeoff. ACS APPLIED MATERIALS & INTERFACES 2020; 12:41471-41476. [PMID: 32820889 DOI: 10.1021/acsami.0c11352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We introduce cracked film lithography (CFL) as a way to reduce the cost of III-V photovoltaics (PV). We spin-coat nanoparticle suspensions onto GaAs thin-film device stacks. The suspensions dry in seconds, forming crack networks that we use as templates through which to electroplate the solar cells' front metal grids. For the first time, we show that heating the crack template allows it to flow and refill cracks, which decreases crack footprint and improves final grid transmittance. We demonstrate 24.7%-efficient single-junction GaAs solar cells using vacuum-free CFL grids. These devices are only 1.7% (absolute) less efficient than the baseline grids patterned by photolithography with the loss mostly resulting from the reduced transparency of the CFL pattern. Additional optimization could decrease this difference. Initial cost modeling suggests that CFL is more scalable than photolithography: In particular, CFL's lower materials and equipment costs could greatly reduce the levelized cost of electricity of III-V PV at scale, a potential step toward terrestrial deployment.
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Affiliation(s)
- Christopher P Muzzillo
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, United States
| | - Evan Wong
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, United States
| | - Lorelle M Mansfield
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, United States
| | - John Simon
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, United States
| | - Aaron J Ptak
- National Renewable Energy Laboratory, 15013 Denver West Pkwy, Golden, Colorado 80401, United States
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8
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Lova P, Soci C. Black GaAs: Gold-Assisted Chemical Etching for Light Trapping and Photon Recycling. MICROMACHINES 2020; 11:mi11060573. [PMID: 32517034 PMCID: PMC7344674 DOI: 10.3390/mi11060573] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/28/2020] [Accepted: 06/04/2020] [Indexed: 11/16/2022]
Abstract
Thanks to its excellent semiconductor properties, like high charge carrier mobility and absorption coefficient in the near infrared spectral region, GaAs is the material of choice for thin film photovoltaic devices. Because of its high reflectivity, surface microstructuring is a viable approach to further enhance photon absorption of GaAs and improve photovoltaic performance. To this end, metal-assisted chemical etching represents a simple, low-cost, and easy to scale-up microstructuring method, particularly when compared to dry etching methods. In this work, we show that the etched GaAs (black GaAs) has exceptional light trapping properties inducing a 120 times lower surface reflectance than that of polished GaAs and that the structured surface favors photon recycling. As a proof of principle, we investigate photon reabsorption in hybrid GaAs:poly (3-hexylthiophene) heterointerfaces.
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Affiliation(s)
- Paola Lova
- Correspondence: ; Tel.: +39-010-353-6192
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9
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Li H, Xie C. Fabrication of Ultra-High Aspect Ratio (>420:1) Al 2O 3 Nanotube Arraysby Sidewall TransferMetal Assistant Chemical Etching. MICROMACHINES 2020; 11:E378. [PMID: 32260150 PMCID: PMC7230905 DOI: 10.3390/mi11040378] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 12/30/2022]
Abstract
We report a robust, sidewall transfer metal assistant chemical etching scheme for fabricating Al2O3 nanotube arrays with an ultra-high aspect ratio. Electron beam lithography followed by low-temperature Au metal assisted chemical etching (MacEtch) is used to pattern high resolution, high aspect ratio, and vertical silicon nanostructures, used as a template. This template is subsequently transferred by an atomic layer deposition of the Al2O3 layer, followed by an annealing process, anisotropic dry etching of the Al2O3 layer, and a sacrificial silicon template. The process and characterization of the Al2O3 nanotube arrays are discussed in detail. Vertical Al2O3 nanotube arrays with line widths as small as 50 nm, heights of up to 21 μm, and aspect ratios up to 420:1 are fabricated on top of a silicon substrate. More importantly, such a sidewall transfer MacEtch approach is compatible with well-established silicon planar processes, and has the benefits of having a fully controllable linewidth and height, high reproducibility, and flexible design, making it attractive for a broad range of practical applications.
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Affiliation(s)
| | - Changqing Xie
- Key Laboratory of Microelectronic Devices & Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, China;
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10
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Romanitan C, Kusko M, Popescu M, Varasteanu P, Radoi A, Pachiu C. Unravelling the strain relaxation processes in silicon nanowire arrays by X-ray diffraction. J Appl Crystallogr 2019. [DOI: 10.1107/s1600576719010707] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Investigations performed on silicon nanowires of different lengths by scanning electron microscopy revealed coalescence processes in longer nanowires. Using X-ray diffraction (XRD), it was found that the shape of the pole figure in reciprocal space is ellipsoidal. This is the signature of lattice defects generated by the relaxation of the strain concentrated in the coalescence regions. This observation is strengthened by the deviation of the XRD peaks from Gaussianity and the appearance of the acoustic phonon mode in the Raman spectrum. It implies that bending, torsion and structural defects coexist in the longer nanowires. To separate these effects, a grazing-incidence XRD technique was conceived which allows the nanowire to be scanned along its entire length. Both ω and φ rocking curves were recorded, and their shapes were used to extract the bending and torsion profiles, respectively, along the nanowire length. Dips were found in both profiles of longer nanowires, while they are absent from shorter ones, and these dips correspond to the regions where both bending and torsion relax. The energy dissipated in the nanowires, which tracks the bending and torsion profiles, has been used to estimate the emergent dislocation density in nanowire arrays.
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11
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Huang HC, Kim M, Zhan X, Chabak K, Kim JD, Kvit A, Liu D, Ma Z, Zuo JM, Li X. High Aspect Ratio β-Ga 2O 3 Fin Arrays with Low-Interface Charge Density by Inverse Metal-Assisted Chemical Etching. ACS NANO 2019; 13:8784-8792. [PMID: 31244033 DOI: 10.1021/acsnano.9b01709] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
β-Ga2O3, with a bandgap of ∼4.6-4.9 eV and readily available bulk substrates, has attracted tremendous interest in the wide bandgap semiconductor community. Producing high aspect ratio β-Ga2O3 3D nanostructures without surface damage is crucial for next-generation power electronics. However, most wet etching methods can only achieve very limited aspect ratios, while dry etch usually damages the surface due to high energy ions. In this work, we demonstrate the formation of β-Ga2O3 fin arrays on a (010) β-Ga2O3 substrate by metal-assisted chemical etching (MacEtch) with high aspect ratio and sidewall surfaces with excellent quality. The etching was found to be strongly crystal orientation dependent, and three kinds of vertical structures were formed after MacEtch. The Schottky barrier height (SBH) between Pt and various MacEtch-produced β-Ga2O3 surfaces and sidewalls was found to decrease as the aspect ratio of the β-Ga2O3 vertical structure increased. This could be attributed to the different amount of oxygen lost at the surface after etching, as indicated by the XPS and TEM examination. Very little hysteresis was observed in the capacitance-voltage characteristics for the 3D Pt/Al2O3/β-Ga2O3 MOS capacitor structures, and the extracted interface trap density was as small as 2.73 × 1011 cm-2 eV-1, comparable to or lower than that for unetched planar β-Ga2O3 surfaces.
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Affiliation(s)
- Hsien-Chih Huang
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Munho Kim
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Xun Zhan
- Department of Materials Science and Engineering, Materials Research Laboratory , University of Illinois , Urbana , Illinois 61801 , United States
| | - Kelson Chabak
- Air Force Research Laboratory, Sensors Directorate , Wright-Patterson AFB , Wright-Patterson AFB , Ohio 45433 , United States
| | - Jeong Dong Kim
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Alexander Kvit
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Dong Liu
- Department of Electrical and Computer Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Zhenqiang Ma
- Department of Materials Science and Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
- Department of Electrical and Computer Engineering , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Jian-Min Zuo
- Department of Materials Science and Engineering, Materials Research Laboratory , University of Illinois , Urbana , Illinois 61801 , United States
| | - Xiuling Li
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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12
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Kim JD, Kim M, Chan C, Draeger N, Coleman JJ, Li X. CMOS-Compatible Catalyst for MacEtch: Titanium Nitride-Assisted Chemical Etching in Vapor phase for High Aspect Ratio Silicon Nanostructures. ACS APPLIED MATERIALS & INTERFACES 2019; 11:27371-27377. [PMID: 31265223 DOI: 10.1021/acsami.9b00871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Metal-assisted chemical etching (MacEtch) is an emerging anisotropic chemical etching technique that has been used to fabricate high aspect ratio semiconductor micro- and nanostructures. Despite its advantages in unparalleled anisotropy, simplicity, versatility, and damage-free nature, the adaptation of MacEtch for silicon (Si)-based electronic device fabrication process is hindered by the use of a gold (Au)-based metal catalyst, as Au is a detrimental deep-level impurity in Si. In this report, for the first time, we demonstrate CMOS-compatible titanium nitride (TiN)-based MacEtch of Si by establishing a true vapor-phase (VP) MacEtch approach in order to overcome TiN-MacEtch-specific challenges. Whereas inverse-MacEtch is observed using conventional liquid phase MacEtch because of the limited mass transport from the strong adhesion between TiN and Si, the true VP etch leads to forward MacEtch and produces Si nanowire arrays by engraving the TiN mesh pattern in Si. The etch rate as a function of etch temperature, solution concentration, TiN dimension, and thickness is systematically characterized to uncover the underlying nature of MacEtching using this new catalyst. VP MacEtch represents a significant step toward scalability of this disruptive technology because of the high controllability of gas phase reaction dynamics. TiN-MacEtch may also have direct implications in embedded TiN-based plasmonic semiconductor structures for photonic applications.
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Affiliation(s)
- Jeong Dong Kim
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Champaign , Illinois 61801 , United States
| | - Munho Kim
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Champaign , Illinois 61801 , United States
| | - Clarence Chan
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Champaign , Illinois 61801 , United States
| | - Nerissa Draeger
- Lam Research Corporation , Fremont , California 94538 , United States
| | - James J Coleman
- Department of Electrical Engineering and Department of Materials Science , University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Xiuling Li
- Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory , University of Illinois at Urbana-Champaign , Champaign , Illinois 61801 , United States
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Chen Y, Zhang C, Li L, Zhou S, Chen X, Gao J, Zhao N, Wong CP. Hybrid Anodic and Metal-Assisted Chemical Etching Method Enabling Fabrication of Silicon Carbide Nanowires. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1803898. [PMID: 30667586 DOI: 10.1002/smll.201803898] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Silicon carbide (SiC) is one of the most important third-generation semiconductor materials. However, the chemical robustness of SiC makes it very difficult to process, and only very limited methods are available to fabricate nanostructures on SiC. In this work, a hybrid anodic and metal-assisted chemical etching (MACE) method is proposed to fabricate SiC nanowires based on wet etching approaches at room temperature and under atmospheric pressure. Through investigations of the etching mechanism and optimal etching conditions, it is found that the metal component plays at least two key roles in the process, i.e., acting as a catalyst to produce hole carriers and introducing band bending in SiC to accumulate sufficient holes for etching. Through the combined anodic and MACE process the required electrical bias is greatly lowered (3.5 V for etching SiC and 7.5 V for creating SiC nanowires) while enhancing the etching efficiency. Furthermore, it is demonstrated that by tuning the etching electrical bias and time, various nanostructures can be obtained and the diameters of the obtained pores and nanowires can range from tens to hundreds of nanometers. This facile method may provide a feasible and economical way to fabricate SiC nanowires and nanostructures for broad applications.
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Affiliation(s)
- Yun Chen
- State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, Guangdong University of Technology, Guangzhou, 510006, China
- School of Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Cheng Zhang
- School of Materials Science and Engineering, Georgia Institute of Technology, 711 Ferst Drive, Atlanta, GA, 30332, USA
| | - Liyi Li
- School of Materials Science and Engineering, Georgia Institute of Technology, 711 Ferst Drive, Atlanta, GA, 30332, USA
| | - Shuang Zhou
- School of Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Xin Chen
- State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, Guangdong University of Technology, Guangzhou, 510006, China
| | - Jian Gao
- State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, Guangdong University of Technology, Guangzhou, 510006, China
| | - Ni Zhao
- School of Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ching-Ping Wong
- School of Materials Science and Engineering, Georgia Institute of Technology, 711 Ferst Drive, Atlanta, GA, 30332, USA
- School of Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong
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14
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Mameli A, Verheijen MA, Mackus AJM, Kessels WMM, Roozeboom F. Isotropic Atomic Layer Etching of ZnO Using Acetylacetone and O 2 Plasma. ACS APPLIED MATERIALS & INTERFACES 2018; 10:38588-38595. [PMID: 30286289 PMCID: PMC6225338 DOI: 10.1021/acsami.8b12767] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Atomic layer etching (ALE) provides Ångström-level control over material removal and holds potential for addressing the challenges in nanomanufacturing faced by conventional etching techniques. Recent research has led to the development of two main classes of ALE: ion-driven plasma processes yielding anisotropic (or directional) etch profiles and thermally driven processes for isotropic material removal. In this work, we extend the possibilities to obtain isotropic etching by introducing a plasma-based ALE process for ZnO which is radical-driven and utilizes acetylacetone (Hacac) and O2 plasma as reactants. In situ spectroscopic ellipsometry measurements indicate self-limiting half-reactions with etch rates ranging from 0.5 to 1.3 Å/cycle at temperatures between 100 and 250 °C. The ALE process was demonstrated on planar and three-dimensional substrates consisting of a regular array of semiconductor nanowires (NWs) conformally covered using atomic layer deposition of ZnO. Transmission electron microscopy studies conducted on the ZnO-covered NWs before and after ALE proved the isotropic nature and the damage-free characteristics of the process. In situ infrared spectroscopy measurements were used to elucidate the self-limiting nature of the ALE half-reactions and the reaction mechanism. During the Hacac etching reaction that is assumed to produce Zn(acac)2, carbonaceous species adsorbed on the ZnO surface are suggested as the cause of the self-limiting behavior. The subsequent O2 plasma step resets the surface for the next ALE cycle. High etch selectivities (∼80:1) over SiO2 and HfO2 were demonstrated. Preliminary results indicate that the etching process can be extended to other oxides such as Al2O3.
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Affiliation(s)
- A. Mameli
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - M. A. Verheijen
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - A. J. M. Mackus
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - W. M. M. Kessels
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
| | - F. Roozeboom
- Department
of Applied Physics, Eindhoven University
of Technology, P.O. Box 513, Eindhoven 5600 MB, The Netherlands
- TNO-Holst
Centre, High Tech Campus
21, Eindhoven 5656 AE, The Netherlands
- E-mail:
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15
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Lova P, Robbiano V, Cacialli F, Comoretto D, Soci C. Black GaAs by Metal-Assisted Chemical Etching. ACS APPLIED MATERIALS & INTERFACES 2018; 10:33434-33440. [PMID: 30191706 DOI: 10.1021/acsami.8b10370] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Large area surface microstructuring is commonly employed to suppress light reflection and enhance light absorption in silicon photovoltaic devices, photodetectors, and image sensors. To date, however, there are no simple means to control the surface roughness of III-V semiconductors by chemical processes similar to the metal-assisted chemical etching of black Si. Here, we demonstrate the anisotropic metal-assisted chemical etching of GaAs wafers exploiting the lower etching rate of the monoatomic Ga<111> and <311> planes. By studying the dependence of this process on different crystal orientations, we propose a qualitative reaction mechanism responsible for the self-limiting anisotropic etching and show that the reflectance of the roughened surface of black GaAs reduces up to ∼50 times compared to polished wafers, nearly doubling its absorption. This method provides a new, simple, and scalable way to enhance light absorption and power conversion efficiency of GaAs solar cells and photodetectors.
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Affiliation(s)
- Paola Lova
- Energy Research Institute at NTU (ERI@N) and Interdisciplinary Graduate School , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798
- School of Physical and Mathematical Sciences, Division of Physics and Applied Physics , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
| | - Valentina Robbiano
- Department of Physics and Astronomy and London Centre for Nanotechnology , University College London , London WC1E 6BT , United Kingdom
| | - Franco Cacialli
- Department of Physics and Astronomy and London Centre for Nanotechnology , University College London , London WC1E 6BT , United Kingdom
| | - Davide Comoretto
- Dipartimento di Chimica e Chimica Industriale , Università degli Studi di Genova , via Dodecaneso 31 , 16121 Genova , Italy
| | - Cesare Soci
- Energy Research Institute at NTU (ERI@N) and Interdisciplinary Graduate School , Nanyang Technological University , 50 Nanyang Avenue , Singapore 639798
- School of Physical and Mathematical Sciences, Division of Physics and Applied Physics , Nanyang Technological University , 21 Nanyang Link , Singapore 637371
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16
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Wilhelm TS, Wang Z, Baboli MA, Yan J, Preble SF, Mohseni PK. Ordered Al xGa 1- xAs Nanopillar Arrays via Inverse Metal-Assisted Chemical Etching. ACS APPLIED MATERIALS & INTERFACES 2018; 10:27488-27497. [PMID: 30079732 DOI: 10.1021/acsami.8b08228] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The ternary III-V semiconductor compound, Al xGa1 -xAs, is an important material that serves a central role within a variety of nanoelectronic, optoelectronic, and photovoltaic devices. With all of its uses, the material itself poses a host of fabrication difficulties stemming from conventional top-down processing, including standard wet-chemical etching and reactive-ion etching (RIE). Metal-assisted chemical etching (MacEtch) techniques provide low-cost and benchtop methods that combine many of the advantages of RIE and wet-chemical etching, without being hindered by many of their disadvantages. Here, inverse-progression MacEtch (I-MacEtch) of Au-patterned Al xGa1 -xAs is demonstrated for the first time and is exploited for the generation of vertical and ordered nanopillar arrays. The etching solution employed here consists of citric acid (C6H8O7) and hydrogen peroxide (H2O2). The I-MacEtch evolution is tracked in time for Al xGa1 -xAs samples with compositions defined by x = 0.55, x = 0.60, and x = 0.70. The vertical and lateral etch rates (VER and LER, respectively) are shown to be tunable with Al fraction and temperature of the etching solution, based on modification of catalytically injected hole distributions. Control over the VER/LER ratio is demonstrated by tailoring etch conditions for single-step fabrication of ordered AlGaAs nanopillar arrays with predefined aspect ratios. Maximum VER and LER values of ∼40 nm/min and ∼105 nm/min, respectively, are measured for Al0.55Ga0.45As at a process temperature of 65 °C. The I-MacEtch nanofabrication methodology outlined in this study may be utilized for the processing of many devices, including high electron mobility transistors, distributed Bragg reflectors, lasers, light-emitting diodes, and multijunction solar cells containing AlGaAs components.
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Affiliation(s)
| | | | | | - Jian Yan
- Matrix Opto Co., Ltd., Suzhou 215614 , China
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17
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Kim M, Yi S, Kim JD, Yin X, Li J, Bong J, Liu D, Liu SC, Kvit A, Zhou W, Wang X, Yu Z, Ma Z, Li X. Enhanced Performance of Ge Photodiodes via Monolithic Antireflection Texturing and α-Ge Self-Passivation by Inverse Metal-Assisted Chemical Etching. ACS NANO 2018; 12:6748-6755. [PMID: 29847725 DOI: 10.1021/acsnano.8b01848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Surface antireflection micro and nanostructures, normally formed by conventional reactive ion etching, offer advantages in photovoltaic and optoelectronic applications, including wider spectral wavelength ranges and acceptance angles. One challenge in incorporating these structures into devices is that optimal optical properties do not always translate into electrical performance due to surface damage, which significantly increases surface recombination. Here, we present a simple approach for fabricating antireflection structures, with self-passivated amorphous Ge (α-Ge) surfaces, on single crystalline Ge (c-Ge) surface using the inverse metal-assisted chemical etching technology (I-MacEtch). Vertical Schottky Ge photodiodes fabricated with surface structures involving arrays of pyramids or periodic nano-indentations show clear improvements not only in responsivity, due to enhanced optical absorption, but also in dark current. The dark current reduction is attributed to the Schottky barrier height increase and self-passivation effect of the i-MacEtch induced α-Ge layer formed on top of the c-Ge surface. The results demonstrated in this work show that MacEtch can be a viable technology for advanced light trapping and surface engineering in Ge and other semiconductor based optoelectronic devices.
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Affiliation(s)
- Munho Kim
- Department of Electrical and Computer Engineering and Micro and Nanotechnology Laboratory, Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Soongyu Yi
- Department of Electrical and Computer Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Jeong Dong Kim
- Department of Electrical and Computer Engineering and Micro and Nanotechnology Laboratory, Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Xin Yin
- Department of Material and Science Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Jun Li
- Department of Material and Science Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Jihye Bong
- Department of Electrical and Computer Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Dong Liu
- Department of Electrical and Computer Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Shih-Chia Liu
- Department of Electrical Engineering , University of Texas at Arlington , Arlington , Texas 76019 , United States
| | - Alexander Kvit
- Materials Science Center , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Weidong Zhou
- Department of Electrical Engineering , University of Texas at Arlington , Arlington , Texas 76019 , United States
| | - Xudong Wang
- Department of Material and Science Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Zongfu Yu
- Department of Electrical and Computer Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Zhenqiang Ma
- Department of Electrical and Computer Engineering , University of Wisconsin at Madison , Madison , Wisconsin 53706 , United States
| | - Xiuling Li
- Department of Electrical and Computer Engineering and Micro and Nanotechnology Laboratory, Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
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18
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Wilhelm TS, Soule CW, Baboli MA, O'Connell CJ, Mohseni PK. Fabrication of Suspended III-V Nanofoils by Inverse Metal-Assisted Chemical Etching of In 0.49Ga 0.51P/GaAs Heteroepitaxial Films. ACS APPLIED MATERIALS & INTERFACES 2018; 10:2058-2066. [PMID: 29303241 DOI: 10.1021/acsami.7b17555] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Metal-assisted chemical etching (MacEtch) has been established as a low-cost, benchtop, and versatile method for large-scale fabrication of semiconductor nanostructures and has been heralded as an alternative to conventional top-down approaches such as reactive-ion etching. However, extension of this technique to ternary III-V compound semiconductor alloys and heteroepitaxial systems has remained relatively unexplored. Here, Au-assisted and inverse-progression MacEtch (I-MacEtch) of the heteroepitaxial In0.49Ga0.51P/GaAs material system is demonstrated, along with a method for fabricating suspended InGaP nanofoils of tunable thickness in solutions of hydrofluoric acid (HF) and hydrogen peroxide (H2O2). A comparison between Au- and Cr-patterned samples is used to demonstrate the catalytic role of Au in the observed etching behavior. Vertical etch rates for nominally undoped, p-type, and n-type InGaP are determined to be ∼9.7, ∼8.7, and ∼8.8 nm/min, respectively. The evolution of I-MacEtch in the InGaP/GaAs system is tracked, leading to the formation of nanocavities located at the center of off-metal windows. Upon nanocavity formation, additional localized mass-transport pathways to the underlying GaAs substrate permit its rapid dissolution. Differential etch rates between the epilayer and substrate are exploited in the fabrication of InGaP nanofoils that are suspended over micro-trenches formed in the GaAs substrate. A model is provided for the observed I-MacEtch mechanism, based on an overlap of neighboring injected hole distribution profiles. The nanofabrication methodology shown here can be applied to various heteroepitaxial III-V systems and can directly impact the conventional processing of device applications in photonics, optoelectronics, photovoltaics, and nanoelectronics.
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Affiliation(s)
- Thomas S Wilhelm
- Microsystems Engineering, Rochester Institute of Technology , Rochester, New York 14623, United States
- NanoPower Research Laboratory, Rochester Institute of Technology , Rochester, New York 14623, United States
| | - Cody W Soule
- Microelectronic Engineering, Rochester Institute of Technology , Rochester, New York 14623, United States
| | - Mohadeseh A Baboli
- Microsystems Engineering, Rochester Institute of Technology , Rochester, New York 14623, United States
- NanoPower Research Laboratory, Rochester Institute of Technology , Rochester, New York 14623, United States
| | - Christopher J O'Connell
- Microelectronic Engineering, Rochester Institute of Technology , Rochester, New York 14623, United States
| | - Parsian K Mohseni
- Microsystems Engineering, Rochester Institute of Technology , Rochester, New York 14623, United States
- NanoPower Research Laboratory, Rochester Institute of Technology , Rochester, New York 14623, United States
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