Nitrogen implantation using a shadow effect to control gate oxide thickness in DRAM semiconductor
US6967147B1 · kind B1 · utility
24Cited by
8References
4Claims
0Family size
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Key dates
| Filing date | Nov 16, 2000 |
| Grant date | Nov 22, 2005 |
| Priority date | — |
| Expiry date | Nov 16, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/981
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Process for forming dual gate oxides for DRAMS by incorporating different thicknesses of gate oxides by using nitrogen implantation. Either angled nitrogen implantation or nitride spacers is used to create a “shadow effect” or area, which limits the nitrogen dose close to the edges of the active area. The reduction of nitrogen dose leads to an increased gate oxide thickness at the active area (AA) adjacent to the shallow trench, increases the threshold of the parasitic corner device and reduces sub Vt (threshold voltage) and junction leakage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.