Method of increasing thickness of field oxide layer
US5972775A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 13, 1998 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Apr 13, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76202
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for increasing the thickness of field oxide layer is provided. At first, a layer of pad oxide and a layer of silicon nitride mask are defined on a semiconductor substrate, and then a field oxide layer, which isolates active device regions, is formed. After the layer of pad oxide and the layer of silicon nitride are removed, a layer of silicon oxide is formed overlying the field oxide layer. The mentioned silicon oxide layer can increase the thickness of field oxide layer for effectively isolating active device regions without enlarging Bird's Beak. The present invention can also effectively improve the Gate Coupling Ratio in a Flash EEPROM.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.