Article
Materials Science, Multidisciplinary
Mohamed Torky, Yanzhen Zhao, Panagiotis Lazos, T. Paul Chow
Summary: This study quantitatively compares the performance potentials and limits for GaN current aperture vertical electron transistors with conventional, doped, and natural polarization superjunction drift layers at 1.2-10 kV breakdown voltage ratings. The specific on-resistance and specific total charge are extracted from simulations representing the static and dynamic performance of each device. A figure-of-merit is used to quantitively compare the performance. The results show that the natural polarization superjunction CAVET exhibits significant improvements in both on-resistance and total charge reduction compared to the doped superjunction and conventional CAVETs.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2023)
Review
Chemistry, Analytical
Catherine Langpoklakpam, An-Chen Liu, Yi-Kai Hsiao, Chun-Hsiung Lin, Hao-Chung Kuo
Summary: This review provides a concise overview of the significance and unique architecture of vertical GaN MOSFETs, discusses their advantages and recent advancements, and suggests methods to enhance their breakdown voltage.
Article
Physics, Multidisciplinary
Yonghe Chen, Ye Yang, Jianghui Zhai, Yuanyuan Sun
Summary: A novel groove-gate power device with a linearly gradient Al composition P-type AlGaN superjunction (LG-SJCAVET) is proposed to overcome the technical challenges of achieving high-aspect-ratio P-type doping in GaN materials. The simulation results demonstrate that the LG-SJCAVET device has higher breakdown voltage and power figure of merit compared to traditional devices and P-type GaN buried layer devices.
FRONTIERS IN PHYSICS
(2023)
Article
Physics, Applied
Vishank Talesara, Yuxuan Zhang, Vijay Gopal Thirupakuzi Vangipuram, Hongping Zhao, Wu Lu
Summary: High power vertical GaN devices on bulk GaN substrates with an optimized guard ring structure were demonstrated, achieving a breakdown voltage of 4.9 kV and a low specific on-resistance of 0.9 mΩ cm(2). The device exhibited a Baliga figure of merit of 27 GW/cm(2) due to the combination of high breakdown voltage and low specific on-resistance.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Genzhuang Li, Yuan Ren, Wang Lin, Qiliang Wang, Liang He, Liuan Li
Summary: A novel quasi-vertical GaN-on-sapphire MPS diode is fabricated by using the p-NiO/n-GaN heterojunction. The MPS diode exhibits a higher turn-on voltage and on-resistance compared to the Ni-anode SBD. The depletion regions at the heterojunction interface effectively enhance the reverse breakdown voltage.
Article
Engineering, Electrical & Electronic
E. Brusaterra, E. Bahat Treidel, F. Brunner, M. Wolf, A. Thies, J. Wurfl, O. Hilt
Summary: By optimizing the doping concentration of gallium nitride drift layers with a given thickness of 5 μm, we were able to improve the high voltage and low resistance performance of vertical electronic devices. Our optimization procedure used an empirical mobility model to maximize the power figure-of-merit of the devices. We grew quasi-vertical gallium nitride-based pn-diodes on sapphire substrates and compared the results to theoretical breakdown voltage values, finding a pn-diode with 545 V avalanche breakdown voltage and a power figure-of-merit of 874 MW/cm(2), as well as a punch-through pn-diode with 920 V breakdown voltage and a power figure-of-merit of 1.48 GW/cm(2).
IEEE ELECTRON DEVICE LETTERS
(2023)
Article
Physics, Applied
Shashwat Rathkanthiwar, Pegah Bagheri, Dolar Khachariya, Seiji Mita, Spyridon Pavlidis, Pramod Reddy, Ronny Kirste, James Tweedie, Zlatko Sitar, Ramon Collazo
Summary: In this study, controlled silicon doping was achieved in GaN films grown by metalorganic chemical vapor deposition. By controlling the electro-chemical potential near the growth surface through chemical potential control and defect quasi-Fermi level point-defect management techniques, carbon-related compensation and mobility collapse were prevented, resulting in a low compensating acceptor concentration.
APPLIED PHYSICS EXPRESS
(2022)
Article
Optics
Kaijie Ji, Kaikang Tian, Yuanbin Gao, Sheng Hang, Chunshuang Chu, Yonghui Zhang, Zi-Hui Zhang
Summary: In this paper, the impact of AlN/GaN distributed Bragg reflector (DBR) and AlInN/GaN DBR on stimulated radiative recombination for GaN-based vertical-cavitysurface-emitting lasers (VCSELs) was investigated using advanced numerical models. It was found that the VCSEL with AlInN/GaN DBR decreases the polarization-induced electric field in the active region, increasing electron-hole radiative recombination. However, the AlInN/GaN DBR has reduced reflectivity compared to the AlN/GaN DBR. The paper suggests the use of more pairs of AlInN/GaN DBR to further increase laser power.
Article
Materials Science, Multidisciplinary
Vishank Talesara, Yuxuan Zhang, Zhaoying Chen, Hongping Zhao, Wu Lu
Summary: The paper presents the design and development of vertical 1.5 kV GaN p-n diodes grown by MOCVD on a HVPE synthesized GaN substrate. These diodes exhibit high breakdown voltage, specific on-resistance, and efficiency, with a positive temperature coefficient suggesting avalanche breakdown mechanism.
JOURNAL OF MATERIALS RESEARCH
(2021)
Article
Engineering, Electrical & Electronic
Georgios Doundoulakis, Dimitris Pavlidis
Summary: The electrical characteristics of simulated vertical gallium nitride nanowire vacuum field emission diodes and transistors were investigated, showing changes in turn-on voltage, saturation emitter current density, and transfer characteristics depending on geometry and material parameters. Sharp-tip GaN nanowires demonstrated decreased turn-on voltage and increased saturation emitter current density, while sharp-tip VFETs displayed reduced threshold voltage, increased transconductance, and improved ON-/OFF-current ratio compared to flat-tip ones. The output characteristics of both types of devices exhibited nonlinear behavior at low voltage regimes.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Chemistry, Analytical
Sung-Hoon Lee, Ho-Young Cha
Summary: This study developed an analytic model for designing a trench MIS FP structure for the edge termination of vertical GaN PN diodes. By considering key parameters and defining boundary conditions, the model was validated through TCAD simulations, demonstrating the effectiveness of the optimized FP structure in achieving desired breakdown voltage characteristics.
Article
Engineering, Electrical & Electronic
Zhengliang Bian, Ke Zeng, Srabanti Chowdhury
Summary: A novel edge termination method has been reported for a 2.8 kV avalanche-capable vertical gallium nitride pn diode. By depositing a field plate on top of a hydrogen-plasma passivated p-type GaN layer, better electric field management was achieved to mitigate peak electric fields in the diode. Avalanche behavior was confirmed by the positive temperature coefficient of the breakdown voltage.
IEEE ELECTRON DEVICE LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Shuzhen You, Karen Geens, Matteo Borga, Hu Liang, Herwig Hahn, Dirk Fahle, Michael Heuken, Kalparupa Mukherjee, Carlo De Santi, Matteo Meneghini, Enrico Zanoni, Martin Berg, Peter Ramvall, Ashutosh Kumar, Mikael T. Bjork, B. Jonas Ohlsson, Stefaan Decoutere
Summary: This paper reviews recent progress and key challenges in process and reliability for high-performance vertical GaN transistors and diodes, with a focus on 200 mm CMOS-compatible technology. It demonstrates the potential of using 200 mm diameter CTE matched substrates for vertical power transistors, and gate module optimizations for device robustness. An alternative technology path based on coalescence epitaxy GaN-on-Silicon is introduced, which could enable thick drift layers of very low dislocation density.
MICROELECTRONICS RELIABILITY
(2021)
Review
Nanoscience & Nanotechnology
Taofei Pu, Usman Younis, Hsien-Chin Chiu, Ke Xu, Hao-Chung Kuo, Xinke Liu
Summary: The article highlights the characteristics of gallium nitride (GaN) material, the development of vertical GaN devices, and their potential in power electronic applications. Vertical GaN-based PN junction diodes have shown significant progress in high epitaxy quality and device structure design, but there is still room for improvement in device epitaxy quality and issues like electrical field crowding effect.
NANOSCALE RESEARCH LETTERS
(2021)
Article
Physics, Applied
Kai Fu, Houqiang Fu, Xuguang Deng, Po-Yi Su, Hanxiao Liu, Kevin Hatch, Chi-Yin Cheng, Daniel Messina, Reza Vatan Meidanshahi, Prudhvi Peri, Chen Yang, Tsung-Han Yang, Jossue Montes, Jingan Zhou, Xin Qi, Stephen M. Goodnick, Fernando A. Ponce, David J. Smith, Robert Nemanich, Yuji Zhao
Summary: The paper investigates the silicon (Si) contamination issue in gallium nitride (GaN) power devices and presents an approach to reduce its impact on device performance. Through optimized etching methods and chemical treatment, the silicon concentration levels at the regrowth interface can be effectively lowered, leading to improved performance in vertical GaN-based p-n diodes.
APPLIED PHYSICS LETTERS
(2021)