Method for making integrated circuit transistors with isolation and substrate connected collectors utilizing simultaneous outdiffusion to convert an epitaxial layer
US4168997A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 10, 1978 |
| Grant date | Sep 25, 1979 |
| Priority date | — |
| Expiry date | Oct 10, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/921
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
In an integrated circuit structure a subsurface isolation layer is doped by diffusion during wafer processing. A substrate is first doped by ion implantation to create surface layer of the opposite conductivity type. Where substrate connections are to be created a heavier deposit of dopant is established using an impurity that will confer conductivity of the same polarity as the substrate. The wafer is then overgrown with an intrinsic layer that will be subsequently doped by diffusion of the ion implanted dopant. Then conventional integrated circuit processing is employed using buried conductive layers, epitaxy, isolation and device diffusion. The transistors thus produced can be designed to have isolation or substrate connected collectors as determined by the substrate surface doping.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.