A recessed-gate In/sub 0.52/Al/sub 0.48/As/n/sup +/-In/sub 0.53/ Ga/sub 0.47/As MIS-type FET

Scaling of the In/sub 0.52/ Al/sub 0.48/As insulator thickness of In/sub 0.52/ Ga/sub 0.48/As/n/sup +/ In/sub 0.53/ Ga/sub 0.47/As MIS (Metal insulator semiconductor) type FETs (field effect transistors) is found experimentally to result in a drastic drop in performance below 200 AA. This is demonstrated to arise from an increase in the sheet resistance of the extrinsic portions of the device that accompanies insulator scaling. In order to solve this problem, a recessed-gate MISFET with a very thin (300 AA) n/sup +/-In/sub 0.53/ Ga/sub 0.47/As cap layer has been fabricated. A 1.5- mu m-long gate device showed a transconductance of 285 mS/mm and a current-gain cutoff frequency of 19.4 GHz. This result proves the ability of a thin n/sup +/-In/sub 0.53/ Ga/sub 0.47/As cap to reduce source resistance and improve device performance. It is concluded that the fabricated recessed-gate structure is a promising candidate for high-performance-scaled MIS-type FETs based on thin, heavily doped In/sub 0.53/ Ga/sub 0.47/As channels.>