The effect of extrinsic capacitances on the microwave performance of Ga/sub 0.51/In/sub 0.49/P/GaAs MISFETs (0 nm/spl les/t/spl les/10 nm) grown by GSMBE

The effect of extrinsic capacitances on the microwave performance of Ga/sub 0.51/In/sub 0.49/P/GaAs MISFETs was first studied experimentally and theoretically by varying the thickness of the Ga/sub 0.51/In/sub 0.49/P insulating layer. MISFETs with airbridge gate structure showed higher f/sub t/s, and f/sub max/s than those of MISFETs with traditional gate structure due to the lower extrinsic capacitances. Moreover, the maximum values of f/sub t/s, and f/sub max/s for a 1 /spl mu/m gate length device all happen when t is between 50 nm and 100 nm. These results demonstrate that Ga/sub 0.51/In/sub 0.49/P/GaAs airbridge gate MISFETs with insulator thickness between 50 nm and 100 nm were very suitable for microwave high power device applications.