Application of selective removal of mesa sidewalls for high-breakdown and high-linearity Ga0.51In0.49P/In0.15Ga0.85 As pseudomorphic transistors

High-linearity Ga0.51In0.49P/In0.15Ga0.85As pseudomorphic high electron-mobility transistors have been successfully fabricated and demonstrated in both direct-current and alternating-current performance. Together with a wide-gap Ga0.51In0.49P gate insulator, a gate-to-drain breakdown voltage of 33 V is further improved to over 40 V by selectively removing mesa sidewalls. The transconductance and current density of a 1 X 100 mu m(2) device at room temperature (77 K) are 90 (120) mS/mm and 646 (780) mA/mm, respectively. The measured f(T) and f(max) are 12 and 28.4 GHz, respectively. These are consistent with 1 mm gate devices when the parasitic capacitance is reduced by selectively removing mesa sidewalls. (C) 1999 American Institute of Physics. [S0003-6951(99)00815-3].