High optical efficiency CMOS image sensor
US8212297B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 2011 |
| Grant date | Jul 3, 2012 |
| Priority date | — |
| Expiry date | Apr 1, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/8033
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
High optical efficiency CMOS image sensors capable of sustaining pixel sizes less than 1.2 microns are provided. Due to high photodiode fill factors and efficient optical isolation, microlenses are unnecessary. Each sensor includes plural imaging pixels having a photodiode structure on a semiconductor substrate adjacent a light-incident upper surface of the image sensor. An optical isolation grid surrounds each photodiode structure and defines the pixel boundary. The optical isolation grid extends to a depth of at least the thickness of the photodiode structure and prevents incident light from penetrating through the incident pixel to an adjacent pixel. A positive diffusion plug vertically extends through a portion of the photodiode structure. A negative diffusion plug vertically extends into the semiconductor substrate for transferring charge generated in the photodiode to a charge collecting region within the semiconductor substrate. Pixel circuitry positioned beneath the photodiode controls charge transfer to image readout circuitry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.