CMOS imager with improved sensitivity
US6169318A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1998 |
| Grant date | Jan 2, 2001 |
| Priority date | — |
| Expiry date | Feb 23, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/803
Abstract
An improved pixel design for a CMOS image sensor with a small feature size is described. In conventional image sensors of this type, the quantum efficiency is typically reduced as a result of the decreased thickness of the top n-type layer of the photodiode and the presence of an intervening p-type layer which is higher doped than the substrate. In the pixel design of the invention, the higher doped p-type layer underneath the photodiode is omitted while barrier regions channel the carriers generated by the impinging radiation towards the top n-layer of the photodiode. A high quantum efficiency is thereby attained in spite of a shrinking feature size. The novel pixel design can also incorporate anti-blooming protection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.