Method of forming dual field oxide isolation
US5369052A · kind A · utility
17Cited by
7References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 6, 1993 |
| Grant date | Nov 29, 1994 |
| Priority date | — |
| Expiry date | Dec 6, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/981
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Dual field oxide isolation (34 & 42) is formed by oxidizing through a portion (44) of a silicon nitride layer (30), through an exposed portion (43) of a remaining portion (18) of a masking layer (16), and through an exposed portion (42) of a buffer layer (28), all of which overlie isolation regions (22) of the silicon substrate (12). The different portions vary the diffusion rate of oxygen so that different field oxide thicknesses are created in a single field oxidation cycle. Therefore, integrated circuits having both low voltage densely packed devices and high voltage devices can be fabricated on the same circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.