Methods of forming bulb-shaped trenches in silicon
US9117759B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 2011 |
| Grant date | Aug 25, 2015 |
| Priority date | — |
| Expiry date | Jan 17, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of creating a trench having a portion of a bulb-shaped cross-section in silicon is disclosed. The method comprises forming at least one trench in silicon and forming a liner in the at least one trench. The liner is removed from a bottom surface of the at least one trench to expose the underlying silicon. A portion of the underlying exposed silicon is removed to form a cavity in the silicon. At least one removal cycle is conducted to remove exposed silicon in the cavity to form a bulb-shaped cross-sectional profile, with each removal cycle comprising subjecting the silicon in the cavity to ozonated water to oxidize the silicon and subjecting the oxidized silicon to a hydrogen fluoride solution to remove the oxidized silicon. A semiconductor device structure comprising the at least one trench comprising a cavity with a bulb-shaped cross-sectional profile is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.