Liquid Phase Oxidized GaAs as Gate Insulator for Enhancement-Mode InGaP/InGaAs Metal-Oxide-Semiconductor Pseudomorphic High-Electron-Mobility Transistor Applications

• Main Authors: Wei-Sheng Chen, 陳瑋昇
• Other Authors: Kuan-Wei Lee
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/36588853812928622135

碩士 === 義守大學 === 電子工程學系碩士班 === 99 === The study uses liquid phase oxidation (LPO) on the GaAs cap layer, and application to enhancement-mode (E-mode) InGaP/InGaAs metal-oxide-semiconductor pseudomorphic high-electron-mobility transistor (MOS-PHEMT) as a gate insulator. Instead of the traditional gate-recess of the cap and Schottky layers, directly oxidation of cap layer would reduce the surface state and simplify the process. The gate dimension of the devices is 1 × 100 μm2. For the DC characteristics, the peak transconductance (gm) and the maximum gate voltage are 141 mS/mm and 2 V, respectively. The subthreshold swing is 66.5 mV/decade, ION/IOFF ratio is in the range of 7.7 x 105 - 2.7 x 106, and the two-terminal gate leakage current density can be improved two orders of magnitude. For the RF characteristics, the cut-off frequencies and maximum oscillation frequencies are 31 GHz and 24 GHz, respectively. The low frequency noises are improved significantly. Furthermore, the thermal effects (250-400 K) of the proposed devices are also discussed. Consequently, the E-mode InGaP/InGaAs MOS-PHEMT with liquid phase oxidized GaAs as gate insulator is promising for low noise and high speed applications.