Enhancement- and depletion-mode InGaP/InGaAs pHEMTs on 6-inch GaAs substrate

The cost effective enhancement-mode (E-mode) and depletion-mode (D-mode) InGaP/InGaAs pseudomorphic high electron mobility transistors (pHEMTs) on 6-inch GaAs substrate have been developed. The 0.5 /spl mu/m gate fingers of E-mode and D-mode pHEMTs are deposited simultaneously in this process simplification. This InGaP/InGaAs E-mode pHEMT exhibits a maximum drain-to-source current (I/sub ds/) of 460 mA/mm, and a maximum transconductance (g/sub m/) of 430 mS/mm. Under 5.2 GHz operation, 216 mW/mm power density, 40% power added efficiency (PAE) and 0.81 dB minimum noise figure (NF/sub min/) are also achieved for E-mode device. In this study, D-mode pHEMTs are applied for switch monolithic microwave integrated circuit (MMIC) which provides an insertion loss of -1.8 dB and an isolation of -9.2 dB under the 28 dBm input power (P/sub in/) and 5.5 GHz operation. From these measured results, this cost effective E/D-mode InGaP/InGaAs pHEMT technology exhibits a highly potential for WLAN applications.