Semiconductor integrated circuit device with high and low voltage wells
US6495896B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1999 |
| Grant date | Dec 17, 2002 |
| Priority date | — |
| Expiry date | Sep 28, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D84/038
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor integrated circuit device comprises an n-type well 8-1 formed in a p-type silicon substrate 1, an n-type well 8-2 formed so as to surround a part of the substrate 1, in which a p−-type well is formed, a p−-type well 15-1 formed in the substrate 1, a p−-type well 15-2 formed in a part of the substrate 1, which is surrounded by the n-type well, an embedded n-type well 12-1 formed below the p−-type well 15-1, and an n-type well 12-2 which is formed below the p−-type well 15-2 and which is connected to the n-type well 8-2. Thus, it is possible to provide a semiconductor integrated circuit device capable of suppressing the increase of the number of photolithography steps and reducing the manufacturing costs.Alternatively, low-voltage n-channel MOS transistors QN1, QN2 and low-voltage p-channel MOS transistors QP1, QP2 are formed in a p-type well 214 and n-type well 213 of a p−-type silicon substrate 211, respectively, and high-voltage n-channel MOS transistors QN3, QN4 are formed in the substrate 211. The p-type well 214, in which the transistors QN1, QN2 are formed, and the p-type element isolating layer 215 of the element isolating r…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.