Method of generating multiple oxides by plasma nitridation on oxide
US7118974B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 2004 |
| Grant date | Oct 10, 2006 |
| Priority date | — |
| Expiry date | Sep 15, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/981
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming multiple gate oxide thicknesses on active areas that are separated by STI isolation regions on a substrate. A first layer of oxide is grown to a thickness of about 50 Angstroms and selected regions are then removed. A second layer of oxide is grown that is thinner than first growth oxide. For three different gate oxide thicknesses, selected second oxide growth regions are nitridated with a N2 plasma which increases the dielectric constant of a gate oxide and reduces the effective oxide thickness. To achieve four different gate oxide thicknesses, nitridation is performed on selected first growth oxides and on selected second growth oxide regions. Nitridation of gate oxides also prevents impurity dopants from migrating across the gate oxide layer and reduces leakage of standby current. The method also reduces corner loss of STI regions caused by HF etchant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.