Control of dopant diffusion from buried layers in bipolar integrated circuits

US8247300B2 · kind B2 · utility

Assignee

• TEXAS INSTRUMENTS INCORPORATED · US

Inventors

• Jeffrey A. Babcock · Neufahrn, DE
• Angelo Pinto · Augusta, IT
• Manfred Schiekofer · Freising, DE
• Scott Balster · Dallas, US
• Gregory E. Howard · Dallas, US
• Alfred Hausler · Freising, DE

Key dates

• Filing date: Nov 30, 2009
• Grant date: Aug 21, 2012
• Expiry date: Apr 11, 2030

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D84/038

Abstract

An integrated circuit and method of fabricating the integrated circuit is disclosed. The integrated circuit includes vertical bipolar transistors (30, 50, 60), each having a buried collector region (26′). A carbon-bearing diffusion barrier (28c) is disposed over the buried collector region (26′), to inhibit the diffusion of dopant from the buried collector region (26′) into the overlying epitaxial layer (28). The diffusion barrier (28c) may be formed by incorporating a carbon source into the epitaxial formation of the overlying layer (28), or by ion implantation. In the case of ion implantation of carbon or SiGeC, masks (52, 62) may be used to define the locations of the buried collector regions (26′) that are to receive the carbon; for example, portions underlying eventual collector contacts (33, 44c) may be masked from the carbon implant so that dopant from the buried collector region (26′) can diffuse upward to meet the contact (33). MOS transistors (70, 80) including the diffusion barrier (28) are also disclosed.