N2O nitrided-oxide trench sidewalls to prevent boron outdiffusion and decrease stress
US6566727B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1999 |
| Grant date | May 20, 2003 |
| Priority date | — |
| Expiry date | Nov 3, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76235
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming an isolation structure in a semiconductor substrate is described. A trench is first etched into a semiconductor substrate. A first oxide layer is then formed with the trench. The first oxide layer is subjected to a nitrogen-oxide gas ambient and is annealed to form an oxy-nitride surface on the first oxide layer and a silicon-oxynitride interface between the first oxide layer and the semiconductor substrate. A second oxide layer is then deposited over the oxy-nitride surface of the first oxide layer. The method and isolation structure of the present invention prevents dopant outdiffusion, reduces trench stresses, allows more uniform growth of thin gate oxides, and permits the use of thinner gate oxides.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.