High voltage capacitor for integrated circuits
US4805071A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 30, 1987 |
| Grant date | Feb 14, 1989 |
| Priority date | — |
| Expiry date | Nov 30, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/435
Abstract
High voltage capacitors particularly suited for a BiCMOS process are formed in conjunction with prior art low voltage capacitors. In a first embodiment of a high voltage capacitor, an N+ region (66) is used as a first plate of the capacitor. The thermal gate oxice layer (48) used in conjunction with the MOS transistors (22,24) is also grown over the N+ region (66). Since the thermal oxide growth over the N+ region is accelerated, a thicker oxide region will be formed. A polysilicon plate (70) is formed over the thick oxide region (68) at the same time the first plate (12) of the low voltage capacitor (10) is formed. Alternatively, a nitride layer (18) may be formed over the thick oxide layer (68). The nitride layer (18) is also used in the formation of a low voltage capacitor (10).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.