Forming air-dielectric isolation regions in a monocrystalline silicon substrate by differential oxidation of polysilicon
US4356211A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 19, 1980 |
| Grant date | Oct 26, 1982 |
| Priority date | — |
| Expiry date | Dec 19, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76227
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Dielectric isolation regions are formed in a monocrystalline silicon substrate through forming trenches in the substrate by reactive ion etching after having etched openings in a layered structure of silicon dioxide and silicon nitride on the surface of the substrate. The walls of the trenches in the substrate are oxidized prior to depositing polycrystalline silicon on the substantially vertical side walls of the trenches in the substrate and on the substantially vertical walls defining the openings in the layered structure. By selectively doping the portion of the polycrystalline silicon on the substantially vertical walls of the openings in the layered structure so that the polycrystalline silicon on the substantially vertical walls of the openings in the layered structure will oxidize at least twice as fast as the polycrystalline silicon on the substantially vertical side walls of the trenches in the substrate, thermal oxidation causes the polycrystalline silicon to close the upper end of each of the trenches while leaving an air space therebeneath to form the dielectric isolation regions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.