Fabrication of normally-off mode GaN and AlGaN/GaN MOSFETs with HfO2 gate insulator

Abstract We have fabricated III-nitride metal-oxide field effect transistors (MOSFETs) using high- k HfO 2 as a gate oxide. Two types of MOSFETs were studied; GaN MOSFETs and AlGaN/GaN MOSFETs. In the case of GaN MOSFETs, the maximum transconductance of 45 mS/mm has been obtained. This is seven times larger than the best-reported value, to our knowledge, for the normally-off GaN MOSFETs with SiO 2 gate oxide. In order to improve the performance of the device, AlGaN/GaN MOSFETs in which high-quality AlGaN/GaN heterointerface is used as a channel have been fabricated. The maximum transconductance and drain current were as high as 160 mS/mm and 840 mA/mm, respectively.

[1]  Yugang Zhou,et al.  High-performance enhancement-mode AlGaN/GaN HEMTs using fluoride-based plasma treatment , 2005, IEEE Electron Device Letters.

[2]  Jiang Li,et al.  Normally-off operation GaN HFET using a thin AlGaN layer for low loss switching devices , 2004 .

[3]  R. J. Gutmann,et al.  Effect of annealing on GaN-insulator interfaces characterized by metal-insulator-semiconductor capacitors , 2003 .

[4]  Yutaka Ohno,et al.  AlGaN/GaN MIS‐HEMTs with HfO2 gate insulator , 2007 .

[5]  Michael S. Shur,et al.  Enhancement mode AlGaN/GaN HFET with selectively grown pn junction gate , 2000 .

[6]  S. Keller,et al.  High-performance E-mode AlGaN/GaN HEMTs , 2006, IEEE Electron Device Letters.

[7]  Koichi Maezawa,et al.  Quasi‐normally‐off AlGaN/GaN HEMTs fabricated by fluoride‐based plasma treatment , 2007 .

[8]  I. Omura,et al.  Recessed-gate structure approach toward normally off high-Voltage AlGaN/GaN HEMT for power electronics applications , 2006, IEEE Transactions on Electron Devices.

[9]  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.

[10]  Guan-Ting Chen,et al.  MgO/p-GaN enhancement mode metal-oxide semiconductor field-effect transistors , 2004 .

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

[12]  K. Brennan,et al.  Electron transport characteristics of GaN for high temperature device modeling , 1998 .

[13]  Drain current DLTS of normally-off AlGaN/GaN HEMTs , 2007 .

[14]  Yugang Zhou,et al.  Control of Threshold Voltage of AlGaN/GaN HEMTs by Fluoride-Based Plasma Treatment: From Depletion Mode to Enhancement Mode , 2006, IEEE Transactions on Electron Devices.

[15]  S. Yoshida,et al.  Normally-off operation power AlGaN/GaN HFET , 2004, 2004 Proceedings of the 16th International Symposium on Power Semiconductor Devices and ICs.

[16]  S. Kishimoto,et al.  Normally-off AlGaN/GaN MOSHFETS with HfO2 gate oxide , 2008 .