FIELD EFFECT TRANSISTOR

摘要

An enhancement type FET using a multi-layer heterojunction has a semi-insulating InP substrate (I) on which is epitaxially grown a non-doped GaInAs layer (2). An n-type GaInAsp layer (3) is epitaxially grown on (2) and an AIInAs layer (5) is epitaxially grown either directly onto (3) or through another InP layer (4). A source electrode (6) and drain electrode (7) with ohmic contacts and a gate electrode (6) and drain electrode (7) with ohmic contacts and a gate electrode (8) with a Schottky contact are formed on (5). The band gap of the FET may be changed stepwise in the direction of thickness by stepwisely changing the comspn. ratio of the transistor in the direction of thickness.