Amorphous Si/Si heterojunction microwave transistors

Abstract

Because the emitter-base junctions of amorphous Si/Si heterojunction bipolar transistors (HBTs) with a conventional structure are inside the amorphous Si (a-Si) layer, their high-frequency performance is limited due to very low electron velocity in a-Si. An improved structure, the two-dimensional-electron-gas (2DEG) emitter structure, is proposed to overcome these problems, and a-Si/Si HBTs with good high-frequency performance are fabricated. Their low-temperature fabrication technology can be extended to other III-V-compound HBTs.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>