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Dascalescu I, Palade C, Slav A, Stavarache I, Cojocaru O, Teodorescu VS, Maraloiu VA, Lepadatu AM, Ciurea ML, Stoica T. Enhancing SiGeSn nanocrystals SWIR photosensing by high passivation in nanocrystalline HfO 2 matrix. Sci Rep 2024; 14:3532. [PMID: 38347024 PMCID: PMC10861535 DOI: 10.1038/s41598-024-53845-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 02/06/2024] [Indexed: 02/15/2024] Open
Abstract
SiGeSn nanocrystals (NCs) in oxides are of considerable interest for photo-effect applications due to the fine-tuning of the optical bandgap by quantum confinement in NCs. We present a detailed study regarding the silicon germanium tin (SiGeSn) NCs embedded in a nanocrystalline hafnium oxide (HfO2) matrix fabricated by using magnetron co-sputtering deposition at room temperature and rapid thermal annealing (RTA). The NCs were formed at temperatures in the range of 500-800 °C. RTA was performed to obtain SiGeSn NCs with surfaces passivated by the embedding HfO2 matrix. The formation of NCs and β-Sn segregation were discussed in relation to the deposition and processing conditions by employing HRTEM, XRD and Raman spectroscopy studies. The spectral photosensitivity exhibited up to 2000 nm in short-wavelength infrared (SWIR) depending on the Sn composition was obtained. Comparing to similar results on GeSn NCs in SiO2 matrix, the addition of Si offers a better thermal stability of SiGeSn NCs, while the use of HfO2 matrix results in better passivation of NCs increasing the SWIR photosensitivity at room temperature. These results suggest that SiGeSn NCs embedded in an HfO2 matrix are a promising material for SWIR optoelectronic devices.
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Affiliation(s)
- Ioana Dascalescu
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania
| | - Catalin Palade
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania
| | - Adrian Slav
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania
| | - Ionel Stavarache
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania
| | - Ovidiu Cojocaru
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania
| | - Valentin Serban Teodorescu
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania
- Academy of Romanian Scientists, 54 Splaiul Independentei, 050094, Bucharest, Romania
| | | | - Ana-Maria Lepadatu
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania.
| | - Magdalena Lidia Ciurea
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania.
- Academy of Romanian Scientists, 54 Splaiul Independentei, 050094, Bucharest, Romania.
| | - Toma Stoica
- National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Romania.
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Zhang XY, Han J, Peng DC, Ruan YJ, Wu WY, Wuu DS, Huang CJ, Lien SY, Zhu WZ. Crystallinity Effect on Electrical Properties of PEALD-HfO 2 Thin Films Prepared by Different Substrate Temperatures. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3890. [PMID: 36364666 PMCID: PMC9656191 DOI: 10.3390/nano12213890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/19/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
Hafnium oxide (HfO2) thin film has remarkable physical and chemical properties, which makes it useful for a variety of applications. In this work, HfO2 films were prepared on silicon through plasma enhanced atomic layer deposition (PEALD) at various substrate temperatures. The growth per cycle, structural, morphology and crystalline properties of HfO2 films were measured by spectroscopic ellipsometer, grazing-incidence X-ray diffraction (GIXRD), X-ray reflectivity (XRR), field-emission scanning electron microscopy, atomic force microscopy and x-ray photoelectron spectroscopy. The substrate temperature dependent electrical properties of PEALD-HfO2 films were obtained by capacitance-voltage and current-voltage measurements. GIXRD patterns and XRR investigations show that increasing the substrate temperature improved the crystallinity and density of HfO2 films. The crystallinity of HfO2 films has a major effect on electrical properties of the films. HfO2 thin film deposited at 300 °C possesses the highest dielectric constant and breakdown electric field.
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Affiliation(s)
- Xiao-Ying Zhang
- Xiamen Key Laboratory of Development and Application for Advanced Semiconductor Coating Technology, School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
| | - Jing Han
- Xiamen Key Laboratory of Development and Application for Advanced Semiconductor Coating Technology, School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
| | - Duan-Chen Peng
- Xiamen Key Laboratory of Development and Application for Advanced Semiconductor Coating Technology, School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
| | - Yu-Jiao Ruan
- National Measurement and Testing Center for Flat Panel Display Industry, Xiamen Institute of Measurement and Testing, Xiamen 361024, China
| | - Wan-Yu Wu
- Department of Materials Science and Engineering, National United University, Miaoli 36063, Taiwan
| | - Dong-Sing Wuu
- Department of Applied Materials and Optoelectronic Engineering, National Chi Nan University, Nantou 54561, Taiwan
| | - Chien-Jung Huang
- Department of Applied Physics, National University of Kaohsiung, Kaohsiung University Rd., Kaohsiung 81148, Taiwan
| | - Shui-Yang Lien
- Xiamen Key Laboratory of Development and Application for Advanced Semiconductor Coating Technology, School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
- Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan
| | - Wen-Zhang Zhu
- Xiamen Key Laboratory of Development and Application for Advanced Semiconductor Coating Technology, School of Opto-Electronic and Communication Engineering, Xiamen University of Technology, Xiamen 361024, China
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Abstract
Group IV quantum dots (QDs) in HfO2 are attractive for non-volatile memories (NVMs) due to complementary metal-oxide semiconductor (CMOS) compatibility. Besides the role of charge storage centers, SiGeSn QDs have the advantage of a low thermal budget for formation, because Sn presence decreases crystallization temperature, while Si ensures higher thermal stability. In this paper, we prepare MOS capacitors based on 3-layer stacks of gate HfO2/floating gate of SiGeSn QDs in HfO2/tunnel HfO2/p-Si obtained by magnetron sputtering deposition followed by rapid thermal annealing (RTA) for nanocrystallization. Crystalline structure, morphology, and composition studies by cross-section transmission electron microscopy and X-ray diffraction correlated with Raman spectroscopy and C–V measurements are carried out for understanding RTA temperature effects on charge storage behavior. 3-layer morphology and Sn content trends with RTA temperature are explained by the strongly temperature-dependent Sn segregation and diffusion processes. We show that the memory properties measured on Al/3-layer stack/p-Si/Al capacitors are controlled by SiGeSn-related trapping states (deep electronic levels) and low-ordering clusters for RTA at 325–450 °C, and by crystalline SiGeSn QDs for 520 and 530 °C RTA. Specific to the structures annealed at 520 and 530 °C is the formation of two kinds of crystalline SiGeSn QDs, i.e., QDs with low Sn content (2 at.%) that are positioned inside the floating gate, and QDs with high Sn content (up to 12.5 at.%) located at the interface of floating gate with adjacent HfO2 layers. The presence of Sn in the SiGe intermediate layer decreases the SiGe crystallization temperature and induces the easier crystallization of the diamond structure in comparison with 3-layer stacks with Ge-HfO2 intermediate layer. High frequency-independent memory windows of 3–4 V and stored electron densities of 1–2 × 1013 electrons/cm2 are achieved.
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