Back side illuminated image sensor with guard ring region reflecting structure
US9685576B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 3, 2014 |
| Grant date | Jun 20, 2017 |
| Priority date | — |
| Expiry date | Apr 4, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/1843
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A photon detector includes a single photon avalanche diode (SPAD) disposed proximate to a front side of a semiconductor layer. The SPAD includes a multiplication junction that is reversed biased above a breakdown voltage such that light directed into the SPAD through a backside of the semiconductor layer triggers an avalanche multiplication process. A guard ring is disposed in a guard ring region that surrounds the SPAD to isolate the SPAD in the semiconductor layer. A guard ring region reflecting structure is disposed in the guard ring region proximate to the guard ring and proximate to the front side of the semiconductor layer such that light directed into the guard ring region through the backside of the semiconductor layer that bypasses the SPAD is redirected by the guard ring region reflecting structure back into the semiconductor layer and into the SPAD.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.