Self‐aligned ohmic contacts technology using Ti plasma etching for GaAs metal Schottky field‐effect transistors

摘要

Bimetal ‘‘T‐gate’’ structures have been obtained by selective Ti‐Al plasma etching. These structures have been used as self‐aligned masks for ohmic contact metallizations. Titanium Schottky diodes exhibit a barrier height of 720 mV with an ideality factor of 1.17. By using only the optical lithographic process, normally on GaAs metal Schottky field‐effect transistors (MESFET) of 1.3‐μm gate length have been fabricated. Transconductance up to 142 mS mm-1 and pinchoff voltage around -2 V have been measured.