Nonalloyed GaAs metal-semiconductor field effect transistor

A novel GaAs metal-semiconductor field-effect transistor (MESFET) with Al0. 25Ga0.75As/GaAs multiquantum barrier (MQB) buffer layer and narrow band InA s/graded InGaAs capping layer was demonstrated. The MQB buffer layer can im prove the sidegating effect and isolation. The capping layer can perform no nalloy ohmic contact with Ti/Pt/Au metals. Furthermore, the Ti/Pt/Au metals directly contact with GaAs active channel layer call work as Schottky barr ier. For the fabrication of this novel MESFET, the thermal alloy and alignm ent processes call be avoided. (C) 2000 Elsevier Science Ltd. All rights re served.