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Yu X, Li Y, He R, Wen Y, Chen R, Xu B, Gao Y. Mechanical regulation to interfacial thermal transport in GaN/diamond heterostructures for thermal switch. NANOSCALE HORIZONS 2024; 9:1557-1567. [PMID: 39016031 DOI: 10.1039/d4nh00245h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Gallium nitride offers an ideal material platform for next-generation high-power electronics devices, which enable a spectrum of applications. The thermal management of the ever-growing power density has become a major bottleneck in the performance, reliability, and lifetime of the devices. GaN/diamond heterostructures are usually adopted to facilitate heat dissipation, given the extraordinary thermal conduction properties of diamonds. However, thermal transport is limited by the interfacial conductance at the material interface between GaN and diamond, which is associated with significant mechanical stress at the atomic level. In this work, we investigate the effect of mechanical strain perpendicular to the GaN/diamond interface on the interfacial thermal conductance of heterostructures using full-atom non-equilibrium molecular dynamics simulations. We found that the heterostructure exhibits severe mechanical stress at the interface in the absence of loading, which is due to lattice mismatch. Upon tensile/compressive loading, the interfacial stress is more pronounced, and the strain is not identical across the interface owing to the contrasting elastic moduli of GaN and diamond. In addition, the interfacial thermal conductance can be notably enhanced and suppressed by tensile and compressive strains, respectively, leading to a 400% variation in thermal conductance. More detailed analyses reveal that the change in interfacial thermal conductance is related to the surface roughness and interfacial bonding strength, as described by a generalized relationship. Moreover, phonon analyses suggest that the unequal mechanical deformation under compressive strain in GaN and diamond induces different frequency shifts in the phonon spectra, leading to an enhancement in phonon overlapping energy, which promotes phonon transport at the interface and elevates the thermal conductance and vice versa for tensile strain. The effect of strain on interface thermal conductance was investigated at various temperatures. Based on the mechanical tunability of thermal conductance, we propose a conceptual design for a mechanical thermal switch that regulates thermal conductance with excellent sensitivity and high responsiveness. This study offers a fundamental understanding of how mechanical strain can adjust interface thermal conductance in GaN/diamond heterostructures with respect to mechanical stress, deformation, and phonon properties. These results and findings lay the theoretical foundation for designing thermal management devices in a strain environment and shed light on developing intelligent thermal devices by leveraging the interplay between mechanics and thermal transport.
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Affiliation(s)
- Xiaotong Yu
- State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Yifan Li
- State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Renjie He
- State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Yanwei Wen
- State Key Laboratory of Material Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, China
| | - Rong Chen
- State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Baoxing Xu
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA 22904, USA.
| | - Yuan Gao
- State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
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Li X, Wan L, Lin C, Huang W, Zhou J, Zhu J, Yang X, Yang X, Zhang Z, Zhu Y, Ren X, Jin Z, Dong L, Cheng S, Li S, Shan C. Interface Modulation for the Heterointegration of Diamond on Si. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309126. [PMID: 38477425 PMCID: PMC11199985 DOI: 10.1002/advs.202309126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/01/2024] [Indexed: 03/14/2024]
Abstract
Along with the increasing integration density and decreased feature size of current semiconductor technology, heterointegration of the Si-based devices with diamond has acted as a promising strategy to relieve the existing heat dissipation problem. As one of the heterointegration methods, the microwave plasma chemical vapor deposition (MPCVD) method is utilized to synthesize large-scale diamond films on a Si substrate, while distinct structures appear at the Si-diamond interface. Investigation of the formation mechanisms and modulation strategies of the interface is crucial to optimize the heat dissipation behaviors. By taking advantage of electron microscopy, the formation of the epitaxial β-SiC interlayer is found to be caused by the interaction between the anisotropically sputtered Si and the deposited amorphous carbon. Compared with the randomly oriented β-SiC interlayer, larger diamond grain sizes can be obtained on the epitaxial β-SiC interlayer under the same synthesis condition. Moreover, due to the competitive interfacial reactions, the epitaxial β-SiC interlayer thickness can be reduced by increasing the CH4/H2 ratio (from 3% to 10%), while further increase in the ratio (to 20%) can lead to the broken of the epitaxial relationship. The above findings are expected to provide interfacial design strategies for multiple large-scale diamond applications.
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Affiliation(s)
- Xing Li
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Li Wan
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Chaonan Lin
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Wen‐Tao Huang
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Jing Zhou
- School of Energy and Power EngineeringKey Lab of Ocean Energy Utilization and Energy Conservation of Ministry of EducationDalian University of TechnologyDalian116024China
| | - Jie Zhu
- School of Energy and Power EngineeringKey Lab of Ocean Energy Utilization and Energy Conservation of Ministry of EducationDalian University of TechnologyDalian116024China
| | - Xun Yang
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Xigui Yang
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Zhenfeng Zhang
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Yandi Zhu
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Xiaoyan Ren
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Ziliang Jin
- State Key Laboratory of Lunar and Planetary SciencesMacau University of Science and TechnologyTaipaMacao999078China
| | - Lin Dong
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Shaobo Cheng
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Shunfang Li
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
| | - Chongxin Shan
- Henan Key Laboratory of Diamond Optoelectronic Materials and DevicesKey Laboratory of Material PhysicsSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou450000China
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3
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Sang L. Well-matched vibrations cool electronic hot spots. Nature 2024; 627:743-744. [PMID: 38443670 DOI: 10.1038/d41586-024-00529-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
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Zhan T, Xu M, Cao Z, Zheng C, Kurita H, Narita F, Wu YJ, Xu Y, Wang H, Song M, Wang W, Zhou Y, Liu X, Shi Y, Jia Y, Guan S, Hanajiri T, Maekawa T, Okino A, Watanabe T. Effects of Thermal Boundary Resistance on Thermal Management of Gallium-Nitride-Based Semiconductor Devices: A Review. MICROMACHINES 2023; 14:2076. [PMID: 38004933 PMCID: PMC10673006 DOI: 10.3390/mi14112076] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/30/2023] [Accepted: 11/04/2023] [Indexed: 11/26/2023]
Abstract
Wide-bandgap gallium nitride (GaN)-based semiconductors offer significant advantages over traditional Si-based semiconductors in terms of high-power and high-frequency operations. As it has superior properties, such as high operating temperatures, high-frequency operation, high breakdown electric field, and enhanced radiation resistance, GaN is applied in various fields, such as power electronic devices, renewable energy systems, light-emitting diodes, and radio frequency (RF) electronic devices. For example, GaN-based high-electron-mobility transistors (HEMTs) are used widely in various applications, such as 5G cellular networks, satellite communication, and radar systems. When a current flows through the transistor channels during operation, the self-heating effect (SHE) deriving from joule heat generation causes a significant increase in the temperature. Increases in the channel temperature reduce the carrier mobility and cause a shift in the threshold voltage, resulting in significant performance degradation. Moreover, temperature increases cause substantial lifetime reductions. Accordingly, GaN-based HEMTs are operated at a low power, although they have demonstrated high RF output power potential. The SHE is expected to be even more important in future advanced technology designs, such as gate-all-around field-effect transistor (GAAFET) and three-dimensional (3D) IC architectures. Materials with high thermal conductivities, such as silicon carbide (SiC) and diamond, are good candidates as substrates for heat dissipation in GaN-based semiconductors. However, the thermal boundary resistance (TBR) of the GaN/substrate interface is a bottleneck for heat dissipation. This bottleneck should be reduced optimally to enable full employment of the high thermal conductivity of the substrates. Here, we comprehensively review the experimental and simulation studies that report TBRs in GaN-on-SiC and GaN-on-diamond devices. The effects of the growth methods, growth conditions, integration methods, and interlayer structures on the TBR are summarized. This study provides guidelines for decreasing the TBR for thermal management in the design and implementation of GaN-based semiconductor devices.
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Affiliation(s)
- Tianzhuo Zhan
- Graduate School of Interdisciplinary New Science, Toyo University, 2100 Kujirai, Kawagoe 350-8585, Saitama, Japan; (S.G.); (T.H.); (T.M.)
- Faculty of Science and Engineering, Waseda University, 3-4-1 Ookubo, Shinjuku-ku 169-8555, Tokyo, Japan; (Z.C.); (C.Z.); (T.W.)
| | - Mao Xu
- School of Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Tokyo, Japan; (M.X.); (A.O.)
| | - Zhi Cao
- Faculty of Science and Engineering, Waseda University, 3-4-1 Ookubo, Shinjuku-ku 169-8555, Tokyo, Japan; (Z.C.); (C.Z.); (T.W.)
| | - Chong Zheng
- Faculty of Science and Engineering, Waseda University, 3-4-1 Ookubo, Shinjuku-ku 169-8555, Tokyo, Japan; (Z.C.); (C.Z.); (T.W.)
| | - Hiroki Kurita
- Graduate School of Environmental Studies, Tohoku University, 6-6-02 Aoba-yama, Sendai 980-8579, Miyagi, Japan; (H.K.); (F.N.)
| | - Fumio Narita
- Graduate School of Environmental Studies, Tohoku University, 6-6-02 Aoba-yama, Sendai 980-8579, Miyagi, Japan; (H.K.); (F.N.)
| | - Yen-Ju Wu
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Ibaraki, Japan; (Y.-J.W.); (Y.X.)
| | - Yibin Xu
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba 305-0047, Ibaraki, Japan; (Y.-J.W.); (Y.X.)
| | - Haidong Wang
- School of Aerospace Engineering, Tsinghua University, Beijing 100084, China;
| | - Mengjie Song
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (M.S.); (W.W.)
| | - Wei Wang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; (M.S.); (W.W.)
| | - Yanguang Zhou
- School of Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China;
| | - Xuqing Liu
- Department of Materials, University of Manchester, Manchester M13 9PL, UK;
| | - Yu Shi
- School of Design, University of Leeds, Woodhouse, Leeds LS2 9JT, UK;
| | - Yu Jia
- School of Engineering and Applied Science, Aston University, Birmingham B4 7ET, UK;
| | - Sujun Guan
- Graduate School of Interdisciplinary New Science, Toyo University, 2100 Kujirai, Kawagoe 350-8585, Saitama, Japan; (S.G.); (T.H.); (T.M.)
| | - Tatsuro Hanajiri
- Graduate School of Interdisciplinary New Science, Toyo University, 2100 Kujirai, Kawagoe 350-8585, Saitama, Japan; (S.G.); (T.H.); (T.M.)
| | - Toru Maekawa
- Graduate School of Interdisciplinary New Science, Toyo University, 2100 Kujirai, Kawagoe 350-8585, Saitama, Japan; (S.G.); (T.H.); (T.M.)
| | - Akitoshi Okino
- School of Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Tokyo, Japan; (M.X.); (A.O.)
| | - Takanobu Watanabe
- Faculty of Science and Engineering, Waseda University, 3-4-1 Ookubo, Shinjuku-ku 169-8555, Tokyo, Japan; (Z.C.); (C.Z.); (T.W.)
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Song Y, Bhattacharyya A, Karim A, Shoemaker D, Huang HL, Roy S, McGray C, Leach JH, Hwang J, Krishnamoorthy S, Choi S. Ultra-Wide Band Gap Ga 2O 3-on-SiC MOSFETs. ACS APPLIED MATERIALS & INTERFACES 2023; 15:7137-7147. [PMID: 36700621 DOI: 10.1021/acsami.2c21048] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Ultra-wide band gap semiconductor devices based on β-phase gallium oxide (Ga2O3) offer the potential to achieve higher switching performance and efficiency and lower manufacturing cost than that of today's wide band gap power electronics. However, the most critical challenge to the commercialization of Ga2O3 electronics is overheating, which impacts the device performance and reliability. We fabricated a Ga2O3/4H-SiC composite wafer using a fusion-bonding method. A low-temperature (≤600 °C) epitaxy and device processing scheme was developed to fabricate MOSFETs on the composite wafer. The low-temperature-grown epitaxial Ga2O3 devices deliver high thermal performance (56% reduction in channel temperature) and a power figure of merit of (∼300 MW/cm2), which is the highest among heterogeneously integrated Ga2O3 devices reported to date. Simulations calibrated based on thermal characterization results of the Ga2O3-on-SiC MOSFET reveal that a Ga2O3/diamond composite wafer with a reduced Ga2O3 thickness (∼1 μm) and a thinner bonding interlayer (<10 nm) can reduce the device thermal impedance to a level lower than that of today's GaN-on-SiC power switches.
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Affiliation(s)
- Yiwen Song
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Arkka Bhattacharyya
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, United States
| | - Anwarul Karim
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Daniel Shoemaker
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hsien-Lien Huang
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 United States
| | - Saurav Roy
- Materials Department, University of California, Santa Barbara, California 93106, United States
| | - Craig McGray
- Modern Microsystems, Gaithersburg, Maryland 20878, United States
| | - Jacob H Leach
- Kyma Technologies, Inc., Raleigh, North Carolina 27617, United States
| | - Jinwoo Hwang
- Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 United States
| | - Sriram Krishnamoorthy
- Materials Department, University of California, Santa Barbara, California 93106, United States
| | - Sukwon Choi
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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Guo H, Li Y, Yu X, Zhou J, Kong Y. Thermal Performance Improvement of AlGaN/GaN HEMTs Using Nanocrystalline Diamond Capping Layers. MICROMACHINES 2022; 13:1486. [PMID: 36144109 PMCID: PMC9505530 DOI: 10.3390/mi13091486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/02/2022] [Accepted: 09/04/2022] [Indexed: 06/16/2023]
Abstract
Nanocrystalline diamond capping layers have been demonstrated to improve thermal management for AlGaN/GaN HEMTs. To improve the RF devices, the application of the technology, the technological approaches and device characteristics of AlGaN/GaN HEMTs with gate length less than 0.5 μm using nanocrystalline diamond capping layers have been studied systematically. The approach of diamond-before-gate has been adopted to resolve the growth of nanocrystalline diamond capping layers and compatibility with the Schottky gate of GaN HEMTs, and the processes of diamond multi-step etching technique and AlGaN barrier protection are presented to improve the technological challenge of gate metal. The GaN HEMTs with nanocrystalline diamond passivated structure have been successfully prepared; the heat dissipation capability and electrical characteristics have been evaluated. The results show the that thermal resistance of GaN HEMTs with nanocrystalline diamond passivated structure is lower than conventional SiN-GaN HEMTs by 21.4%, and the mechanism of heat transfer for NDC-GaN HEMTs is revealed by simulation method in theory. Meanwhile, the GaN HEMTs with nanocrystalline diamond passivated structure has excellent output, small signal gain and cut-off frequency characteristics, especially the current-voltage, which has a 27.9% improvement than conventional SiN-GaN HEMTs. The nanocrystalline diamond capping layers for GaN HEMTs has significant performance advantages over the conventional SiN passivated structure.
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Affiliation(s)
- Huaixin Guo
- Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing 210016, China
- Nanjing Electronic Devices Institute, Nanjing 210016, China
| | - Yizhuang Li
- Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing 210016, China
| | - Xinxin Yu
- Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing 210016, China
| | - Jianjun Zhou
- Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing 210016, China
| | - Yuechan Kong
- Science and Technology on Monolithic Integrated Circuits and Modules Laboratory, Nanjing 210016, China
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Mendes JC, Liehr M, Li C. Diamond/GaN HEMTs: Where from and Where to? MATERIALS 2022; 15:ma15020415. [PMID: 35057131 PMCID: PMC8778208 DOI: 10.3390/ma15020415] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/03/2021] [Accepted: 12/30/2021] [Indexed: 12/07/2022]
Abstract
Gallium nitride is a wide bandgap semiconductor material with high electric field strength and electron mobility that translate in a tremendous potential for radio-frequency communications and renewable energy generation, amongst other areas. However, due to the particular architecture of GaN high electron mobility transistors, the relatively low thermal conductivity of the material induces the appearance of localized hotspots that degrade the devices performance and compromise their long term reliability. On the search of effective thermal management solutions, the integration of GaN and synthetic diamond with high thermal conductivity and electric breakdown strength shows a tremendous potential. A significant effort has been made in the past few years by both academic and industrial players in the search of a technological process that allows the integration of both materials and the fabrication of high performance and high reliability hybrid devices. Different approaches have been proposed, such as the development of diamond/GaN wafers for further device fabrication or the capping of passivated GaN devices with diamond films. This paper describes in detail the potential and technical challenges of each approach and presents and discusses their advantages and disadvantages.
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Affiliation(s)
- Joana C. Mendes
- Instituto de Telecomunicações e Departamento de Eletrónica, Telecomunicações e Informática, Universidade de Aveiro, 3810-193 Aveiro, Portugal
- Correspondence:
| | - Michael Liehr
- W&L Coating Systems GmbH, Bingenheimer Str. 32, D-61203 Reichelsheim, Germany; (M.L.); (C.L.)
| | - Changhui Li
- W&L Coating Systems GmbH, Bingenheimer Str. 32, D-61203 Reichelsheim, Germany; (M.L.); (C.L.)
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Malakoutian M, Field DE, Hines NJ, Pasayat S, Graham S, Kuball M, Chowdhury S. Record-Low Thermal Boundary Resistance between Diamond and GaN-on-SiC for Enabling Radiofrequency Device Cooling. ACS APPLIED MATERIALS & INTERFACES 2021; 13:60553-60560. [PMID: 34875169 DOI: 10.1021/acsami.1c13833] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The implementation of 5G-and-beyond networks requires faster, high-performance, and power-efficient semiconductor devices, which are only possible with materials that can support higher frequencies. Gallium nitride (GaN) power amplifiers are essential for 5G-and-beyond technologies since they provide the desired combination of high frequency and high power. These applications along with terrestrial hub and backhaul communications at high power output can present severe heat removal challenges. The cooling of GaN devices with diamond as the heat spreader has gained significant momentum since device self-heating limits GaN's performance. However, one of the significant challenges in integrating polycrystalline diamond on GaN devices is maintaining the device performance while achieving a low diamond/GaN channel thermal boundary resistance. In this study, we achieved a record-low thermal boundary resistance of around 3.1 ± 0.7 m2 K/GW at the diamond/Si3N4/GaN interface, which is the closest to theoretical prediction to date. The diamond was integrated within ∼1 nm of the GaN channel layer without degrading the channel's electrical behavior. Furthermore, we successfully minimized the residual stress in the diamond layer, enabling more isotropic polycrystalline diamond growth on GaN with thicknesses >2 μm and a ∼1.9 μm lateral grain size. More isotropic grains can spread the heat in both vertical and lateral directions efficiently. Using transient thermoreflectance, the thermal conductivity of the grains was measured to be 638 ± 48 W/m K, which when combined with the record-low thermal boundary resistance makes it a leading-edge achievement.
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Affiliation(s)
- Mohamadali Malakoutian
- Department of Electrical Engineering, Stanford University, Stanford, California 94305-6104, United States
| | - Daniel E Field
- Center for Device Thermography and Reliability, University of Bristol, Bristol BS8 1TL, U.K
| | - Nicholas J Hines
- George W. Woodruff School of Mechanical Engineering and Heat Lab, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, United States
| | - Shubhra Pasayat
- Department of Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Samuel Graham
- George W. Woodruff School of Mechanical Engineering and Heat Lab, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, United States
| | - Martin Kuball
- Center for Device Thermography and Reliability, University of Bristol, Bristol BS8 1TL, U.K
| | - Srabanti Chowdhury
- Department of Electrical Engineering, Stanford University, Stanford, California 94305-6104, United States
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Sznajder M, Hrytsak R. DFT-Based Studies on Carbon Adsorption on the wz-GaN Surfaces and the Influence of Point Defects on the Stability of the Diamond-GaN Interfaces. MATERIALS 2021; 14:ma14216532. [PMID: 34772058 PMCID: PMC8585404 DOI: 10.3390/ma14216532] [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: 10/04/2021] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 11/26/2022]
Abstract
Integration of diamond with GaN-based high-electron-mobility transistors improves thermal management, influencing the reliability, performance, and lifetime of GaN-based devices. The current GaN-on-diamond integration technology requires precise interface engineering and appropriate interfacial layers. In this respect, we performed first principles calculation on the stability of diamond–GaN interfaces in the framework of density functional theory. Initially, some stable adsorption sites of C atoms were found on the Ga- and N-terminated surfaces that enabled the creation of a flat carbon monolayer. Following this, a model of diamond–GaN heterojunction with the growth direction [111] was constructed based on carbon adsorption results on GaN{0001} surfaces. Finally, we demonstrate the ways of improving the energetic stability of diamond–GaN interfaces by means of certain reconstructions induced by substitutional dopants present in the topmost GaN substrate’s layer.
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Affiliation(s)
- Malgorzata Sznajder
- Institute of Physics, College of Natural Sciences, University of Rzeszow, Pigonia 1, 35-959 Rzeszow, Poland;
- Correspondence:
| | - Roman Hrytsak
- Institute of Physics, College of Natural Sciences, University of Rzeszow, Pigonia 1, 35-959 Rzeszow, Poland;
- Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland
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Soleimanzadeh R, Naamoun M, Floriduz A, Khadar RA, van Erp R, Matioli E. Seed Dibbling Method for the Growth of High-Quality Diamond on GaN. ACS APPLIED MATERIALS & INTERFACES 2021; 13:43516-43523. [PMID: 34464085 DOI: 10.1021/acsami.1c08761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The integration of diamond and GaN has been highly pursued for thermal management purposes as well as combining their exceptional complementary properties for power electronics applications and novel semiconductor heterostructures. However, the growth of diamond-on-GaN is challenging due to the high lattice and thermal expansion mismatches. The weak adhesion of diamond to GaN and high residual stresses after the deposition often result in the diamond film delamination or development of cracks, which hinder the subsequent device fabrication. Here, we present a new seed dibbling method for seeding and growing high-quality diamond films on foreign substrates, in particular on cost-effective GaN-on-Si, with significantly improved adhesion. Diamond films grown conformally on patterned GaN-on-Si presented high quality with significantly larger grains and a 95% sp3/sp2 ratio, excellent interface between diamond and GaN, and lower residual stresses (as low as 0.2 GPa) compared to conventional methods. In addition, the method provided excellent adhesion, enabling a reliable polishing of the as-grown diamond films on GaN on Si without any delamination, resulting in smooth diamond-on-GaN substrates with subnanometer root-mean-square roughness. Diamond layers deposited via seed dibbling resulted in a 2-fold improvement in the effective thermal conductivity for GaN-on-Si with only a 20 μm thick diamond layer. This method opens many new possibilities for the development of high-performance power electronic devices and integrated devices with excellent thermal management based on a diamond-on-GaN platform. In addition, this technique could be extended to other substrates to combine the outstanding properties of diamond with other kinds of devices.
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Affiliation(s)
| | - Mehdi Naamoun
- Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland
| | | | | | - Remco van Erp
- Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland
| | - Elison Matioli
- Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland
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