Pixels with photodiodes formed from epitaxial silicon
US9812489B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 19, 2016 |
| Grant date | Nov 7, 2017 |
| Priority date | — |
| Expiry date | Apr 19, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F71/128
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An image sensor may include a plurality of pixels that each contain a photodiode. The pixels may include deep photodiodes for near infrared applications. The photodiodes may be formed by growing doped epitaxial silicon in trenches formed in a substrate. The doped epitaxial silicon may be doped with phosphorus or arsenic. The pixel may include additional n-wells formed by implanting ions in the substrate. Isolation regions formed by implanting boron ions may isolate the n-wells and doped epitaxial silicon. The doped epitaxial silicon may be formed at temperatures between 500° C. and 550° C. After forming the doped epitaxial silicon, laser annealing may be used to activate the ions. Chemical mechanical planarization may also be performed to ensure that the doped epitaxial silicon has a flat and planar surface for subsequent processing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.