Isotropic silicon and silicon-germanium etching with tunable selectivity
US9984890B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 2017 |
| Grant date | May 29, 2018 |
| Priority date | — |
| Expiry date | Mar 2, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/121
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Isotropic silicon and silicon-germanium etching with tunable selectivity is described. The method includes receiving a substrate having a layer of silicon and a layer of silicon-germanium with sidewall surfaces of silicon and silicon-germanium being uncovered, positioning the substrate in a processing chamber configured for etching substrates, and modifying uncovered surfaces of silicon and silicon-germanium by exposing the uncovered surfaces of silicon and silicon-germanium to radical species. The method further includes executing a gaseous chemical oxide removal process that includes flowing a mixture of a nitrogen-containing gas and a fluorine-containing gas at a first substrate temperature to form a fluorine byproduct followed by executing a sublimation process to remove the fluorine byproduct at a second substrate temperature that is higher than the first substrate temperature, and controlling the second substrate temperature to tune the sublimation rate and etch selectivity of a silicon oxide material relative to a silicon-germanium oxide material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.