Electrical Characteristics of Enhancement-Mode n-Channel Vertical GaN MOSFETs and the Effects of Sidewall Slope

Gallium nitride (GaN) is a promising material for next-generation high-power applications due to its wide bandgap, high breakdown field, high electron mobility, and good thermal conductivity. From a structure point of view, the vertical device is more suitable to high-power applications than planar devices because of its area effectiveness. However, it is challenging to obtain a completely upright vertical structure due to inevitable sidewall slope in anisotropic etching of GaN. In this letter, we design and analyze the enhancement-mode n-channel vertical GaN MOSFET with variation of sidewall gate angle by two-dimensional (2D) technology computer-aided design (TCAD) simulations. As the sidewall slope gets closer to right angle, the device performances are improved since a gradual slope provides a leakage current path through the bulk region.

[1]  Fumio Horiguchi,et al.  High performance CMOS surrounding gate transistor (SGT) for ultra high density LSIs , 1988, Technical Digest., International Electron Devices Meeting.

[2]  M. Shur,et al.  Monte Carlo simulation of electron transport in gallium nitride , 1993 .

[3]  P. Janke,et al.  GaN/AlGaN high electron mobility transistors with f τ of 110 GHz , 2000 .

[4]  Shreepad Karmalkar,et al.  Enhancement of breakdown voltage in AlGaN/GaN high electron mobility transistors using a field plate , 2001 .

[5]  O. W. Holland,et al.  Improved inversion channel mobility for 4H-SiC MOSFETs following high temperature anneals in nitric oxide , 2001, IEEE Electron Device Letters.

[6]  Michael S. Shur,et al.  Induced strain mechanism of current collapse in AlGaN/GaN heterostructure field-effect transistors , 2001 .

[7]  T. Kazior,et al.  Trapping effects in GaN and SiC microwave FETs , 2002, Proc. IEEE.

[8]  G. Meneghesso,et al.  Surface-related drain current dispersion effects in AlGaN-GaN HEMTs , 2004, IEEE Transactions on Electron Devices.

[9]  K. Matocha,et al.  High-voltage normally off GaN MOSFETs on sapphire substrates , 2005, IEEE Transactions on Electron Devices.

[10]  U. Mishra,et al.  Ion implanted AlGaN-GaN HEMTs with nonalloyed Ohmic contacts , 2005, IEEE Electron Device Letters.

[11]  Yongho Oh,et al.  Gate Workfunction Optimization of a 32 nm Metal Gate MOSFET for Low Power Applications , 2006 .

[12]  T. Khan,et al.  Enhancement-Mode n-Channel GaN MOSFETs on p and n-GaN/Sapphire Substrates , 2006, 2006 IEEE International Symposium on Power Semiconductor Devices and IC's.

[13]  Hirotaka Otake,et al.  Vertical GaN-Based Trench Gate Metal Oxide Semiconductor Field-Effect Transistors on GaN Bulk Substrates , 2008 .

[14]  Umesh K. Mishra,et al.  GaN-Based RF Power Devices and Amplifiers , 2008, Proceedings of the IEEE.

[15]  N. Hara,et al.  Enhancement-Mode GaN MIS-HEMTs With n-GaN/i-AlN/n-GaN Triple Cap Layer and High- $k$ Gate Dielectrics , 2010, IEEE Electron Device Letters.

[16]  Hiroshi Yano,et al.  Improved Inversion Channel Mobility in 4H-SiC MOSFETs on Si Face Utilizing Phosphorus-Doped Gate Oxide , 2010, IEEE Electron Device Letters.

[17]  Byung-Gook Park,et al.  Analyses on Small-Signal Parameters and Radio-Frequency Modeling of Gate-All-Around Tunneling Field-Effect Transistors , 2011, IEEE Transactions on Electron Devices.

[18]  S. Yaegassi,et al.  Vertical heterojunction field‐effect transistors utilizing re‐grown AlGaN/GaN two‐dimensional electron gas channels on GaN substrates , 2011 .

[19]  K. Seo,et al.  Field Plated AlGaN/GaN-on-Si HEMTs for High Voltage Switching Applications , 2011 .

[20]  Min-Seok Kang,et al.  Impact of Interface Charges on the Transient Characteristics of 4H-SiC DMOSFETs , 2012 .

[21]  Shu Yang,et al.  Effective Passivation of AlGaN/GaN HEMTs by ALD-Grown AlN Thin Film , 2012, IEEE Electron Device Letters.

[22]  J. Kwak,et al.  Effect of electron-beam irradiation on leakage current of AlGaN/GaN HEMTs on sapphire , 2013 .

[23]  Jung-Hee Lee,et al.  Influence of Series Resistance and Interface State Density on Electrical Characteristics of Ru/Ni/n-GaN Schottky structure , 2013 .

[24]  Shu Yang,et al.  Mechanism of PEALD-Grown AlN Passivation for AlGaN/GaN HEMTs: Compensation of Interface Traps by Polarization Charges , 2013, IEEE Electron Device Letters.

[25]  Min-Ki Kim,et al.  High-Voltage AlGaN/GaN High-Electron-Mobility Transistors Using Thermal Oxidation for NiO x Passivation , 2013 .

[26]  M. Pandian,et al.  Analytical Threshold Voltage Modeling of Surrounding Gate Silicon Nanowire Transistors with Different Geometries , 2014 .

[27]  P. Anandan,et al.  Optimization and Characterization of Gate Electrode Dependent Flicker Noise in Silicon Nanowire Transistors , 2014 .

[28]  Hee-Jun Kim,et al.  A Novel Circuit for Characteristics Measurement of SiC Transistors , 2014 .