Method for fabricating a bipolar transistor
US4701998A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1985 |
| Grant date | Oct 27, 1987 |
| Priority date | — |
| Expiry date | Dec 2, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/118
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for fabricating a bipolar transistor having a base doping variation of less than 20% is disclosed. A polysilicon base contact bipolar transistor is formed up to the point just prior to the intrinsic base-emitter formation. The intrinsic base-emitter opening is then reactive ion etched through the polysilicon base contact layer down to and into a single crystal silicon body thereunder, whereby the surface of the single crystal silicon is damaged. A silicon dioxide layer is then grown on the exposed and damaged single crystal silicon to convert the damaged silicon surface into a silicon dioxide layer. The silicon dioxide layer is removed by chemical etching to expose undamaged single crystal silicon. A screen silicon dioxide layer 50 to 500 .ANG..+-.10%, e.g., 180 .ANG., is then formed on the thus exposed undamaged single crystal silicon. The intrinsic base region is then formed by ion implantation through the screen silicon dioxide layer, the emitter region is formed within the intrinsic base region and electrical contact is made to the various elements of the bipolar transistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.