Silicon-germanium bipolar transistor with optimized germanium profile

US6750483B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Wolfgang Klein · Zorneding, DE
• Rudolf Lachner · Ingolstadt, DE
• Wolfgang Molzer · Ottobrunn, DE

Key dates

• Filing date: Jul 22, 2002
• Grant date: Jun 15, 2004
• Expiry date: Jul 22, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D10/891

Abstract

A silicon-germanium bipolar transistor includes a silicon substrate in which a first n-doped emitter region, a second p-doped base region adjoining the latter and a third n-doped collector region adjoining the latter, are formed. A first space charge zone is formed between the emitter region and the base region and a second space charge zone is formed between the base region and the collector region. The base region and an edge zone of the adjoining emitter region are alloyed with germanium. The germanium concentration in the emitter region rises toward the base region. The germanium concentration in a junction region containing the first space charge zone rises less sharply than in the emitter region or decreases and, in the base region, it initially again rises more sharply than in the junction region.