Method of fabricating an ultra-thin active region for high speed semiconductor devices
US5177025A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 1992 |
| Grant date | Jan 5, 1993 |
| Priority date | — |
| Expiry date | Jan 24, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/936
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of fabricating a semiconductor device to retard diffusion of a dopant from a center active region into adjacent regions. The center active region is epitaxially formed by selectively increasing and decreasing an introduction of diffusion-suppressing material, preferably germanium, into a semiconductor material, preferably silicon, so that a vertical profile of the content of the diffusion-suppressing material is such that outdiffusion of a dopant is minimized. One embodiment of the tailoring is to increase the concentration of the diffusion-suppressing material at both of the opposed sides of a base region of a bipolar transistor, thereby providing concentration peaks at the interfaces of the base region with collector and emitter regions. The concentration of germanium in a Si.sub.1-x Ge.sub.x layer is such that the value x is within the range 0.08 to 0.35 and optimally within the range 0.15 to 0.31. The dopant, preferably boron, also has a tailored concentration profile to minimize outdiffusion. A thinner, more highly doped active region is thereby achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.