Fabrication of bipolar transistors using selective doping to improve performance characteristics

US5698459A · kind A · utility

Assignee

• NATIONAL SEMICONDUCTOR CORPORATION · US

Inventors

• Michael J. Grubisich · San Jose, US
• Constantin Bulucea · Milpitas, US

Key dates

• Filing date: Jun 1, 1995
• Grant date: Dec 16, 1997
• Expiry date: Jun 1, 2015

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S148/01

Abstract

Parts of the emitter and base of a vertical bipolar transistor adjoin a field-isolation region to form a walled-emitter structure. The transistor is furnished with extra doping in the collector and, optionally, in the base. The extra collector doping is provided along collector-base junction below the intrinsic base to create a special collector zone spaced laterally apart from the field-isolation region. The presence of the special collector zone causes the intrinsic base to be thinner, thereby raising the cutoff frequency and overall current gain. The extra base doping is provided in the intrinsic base along the field-isolation region to improve the transistor's breakdown voltage and leakage current characteristics.