Normally-off high-voltage p-GaN gate GaN HFET with carbon-doped buffer

Normally-off GaN transistors for power applications in p-type GaN gate technology with a modified carbon-doped GaN buffer are presented. A combination of an AlGaN back-barrier with the carbon-doped buffer prevents early off-state punch-through. Simultaneously, the on-state resistance could be kept low and the threshold voltage with 1.1 V high enough for secure normally-off operation. 1000 V breakdown strength has been obtained for devices with 6 μm gate-drain spacing. The resulting breakdown scaling slope is 170 V/μm gate-drain distance. The on-state resistance is 7.4 Ωmm. The resulting VBr-to-RONA ratio (1000 V, 0.62 mΩcm2) is beyond so far reported ratios for normally-off GaN transistors. Modifications of the p-type GaN layer have shown to additionally increase the threshold voltage by 0.4 V without paying a price in the on-state resistance of the device.

[1]  S. Keller,et al.  High Breakdown Voltage Achieved on AlGaN/GaN HEMTs With Integrated Slant Field Plates , 2006, IEEE Electron Device Letters.

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

[3]  Frank Brunner,et al.  AlGaN/GaN/GaN:C Back-Barrier HFETs With Breakdown Voltage of Over 1 kV and Low $R_{\scriptscriptstyle{\rm ON}} \times A$ , 2010, IEEE Transactions on Electron Devices.

[4]  Osamu Machida,et al.  Normally-off AlGaN/GaN HFETs using NiOx gate with recess , 2009, 2009 21st International Symposium on Power Semiconductor Devices & IC's.

[5]  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.

[6]  J. Wurfl,et al.  Normally-off AlGaN/GaN HFET with p-type Ga Gate and AlGaN buffer , 2010, 2010 22nd International Symposium on Power Semiconductor Devices & IC's (ISPSD).

[7]  J. Wurfl,et al.  Punchthrough-Voltage Enhancement of AlGaN/GaN HEMTs Using AlGaN Double-Heterojunction Confinement , 2008, IEEE Transactions on Electron Devices.

[8]  H. Ishida,et al.  Gate Injection Transistor (GIT)—A Normally-Off AlGaN/GaN Power Transistor Using Conductivity Modulation , 2007, IEEE Transactions on Electron Devices.

[9]  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.

[10]  Eldad Bahat Treidel,et al.  Normally-off AlGaN/GaN HFET with p-type GaN gate and AlGaN buffer , 2010, 2010 6th International Conference on Integrated Power Electronics Systems.