Compound semiconductor bipolar transistor

US5726468A · kind A · utility

Assignee

• Mitsubishi Electric Corporation · JP

Inventors

• Tomoki Oku · Itami, JP
• Hirofumi Nakano · Hitachinaka, JP
• Shinichi Miyakuni · Itami, JP
• Teruyuki Shimura · Tokyo, JP
• Ryo Hattori · Tokyo, JP

Key dates

• Filing date: Mar 13, 1996
• Grant date: Mar 10, 1998
• Expiry date: Mar 13, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D64/281

Abstract

A semiconductor device includes a semiconductor substrate; a first active layer disposed on the semiconductor substrate; a second active layer disposed on the first active layer; a first electrode including a lower stage disposed on the second active layer and an upper stage disposed on the lower stage and having an overhanging portion protruding from the lower stage; an insulating film continuously covering a surface of the second active layer, a side surface of the lower stage of the first electrode, and a lower surface and a side surface of the overhanging portion of the upper stage; and a second electrode disposed on the surface of the first active layer at opposite sides of the second active layer, self-aligned with the second active layer. The distance between the second electrode and the second active layer is minimized and the thickness of the second electrode can be about 7000 .ANG., minimizing the resistance of the first active layer and improving high frequency characteristics. Electrical separation between the first and second active layers can be achieved reliably. Recombination at the surface of the second active layer is suppressed.