Method for fabricating a multilayer epitaxial structure
US5432121A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 16, 1994 |
| Grant date | Jul 11, 1995 |
| Priority date | — |
| Expiry date | May 16, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/041
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An all epitaxial process performed entirely in a CVD reactor is employed to grow epitaxial layers with accurately controlled successively low and high dopant concentrations over a heavily doped substrate, eliminating the need for a separate diffusion, even for high purity concentrations. After purging the reactor system, the heavily doped silicon substrate is "capped" by growing two successive very thin silicon sublayers of the same conductivity type. The reactor chamber is subjected to a hydrogen purge to deplete any contaminents after each sublayer is formed. The cap sublayers form a narrow, abrupt intrinsic transition region with the substrate and become an active part of the device structure. A lightly doped epitaxial layer is grown over the "capped" substrate so that a depletion region can be formed in the device under suitable reverse bias. A heavily doped epitaxial layer is then grown over the lightly doped epitaxial layer. The heavily doped epitaxial layer forms a contact layer and has a polarity opposite to that of the substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.