Field effect transistor

US5811843A · kind A · utility

Assignee

• Mitsubishi Electric Corporation · JP

Inventors

• Yoshitsugu Yamamoto · Tokyo, JP
• Norio Hayafuji · Itami, JP

Key dates

• Filing date: Feb 24, 1997
• Grant date: Sep 22, 1998
• Expiry date: Feb 24, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D30/4732

Abstract

A field effect transistor includes a semi-insulating III-V compound semiconductor substrate; a channel layer disposed on the substrate; an n type electron supply layer disposed on the channel layer and comprising a mixed crystalline compound semiconductor layer including AlAs; an n type ohmic contact layer disposed on the electron supply layer; source and drain electrodes disposed on the ohmic contact layer; an opening in a region between the source and drain electrodes penetrating the ohmic contact layer; a gate electrode disposed in the opening and making a Schotty contact; and a surface protection film of a semiconductor material free of Al, In, and As, covering the opening except where the gate electrode is present. Fluorine is prevented from getting into the electron supply layer with no increase in transconductance or source resistance by providing a layer between the source and a channel, and between the gate and the channel.