Method to increase conversion gain of an active pixel, and corresponding active pixel

US6545303B1 · kind B1 · utility

Assignee

• Fillfactory · BE

Inventor

• Danny Scheffer · Hulst, NL

Key dates

• Filing date: Nov 6, 2001
• Grant date: Apr 8, 2003
• Expiry date: Nov 6, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F39/18

Abstract

The present invention provides an active pixel including a semiconductor layer (5) having dopants of a first conductivity type, wherein said semiconductor layer (5) comprises a first region (1) and a second region (2) both having dopants of a second conductivity type, said first region (1) and said second region (2) being adapted for collecting charge carriers in said semiconductor layer (5) generated by electromagnetic radiation, said first region (1) having an area and a boundary of this area, said semiconductor layer (5) further comprising a third region (3) having dopants of the first conductivity type at a higher doping level than the semiconductor layer (5), the third region (3) forming a barrier for substantially impeding the diffusion of said charge carriers to said second region (2). Over a part of its boundary, the first region (1) is separated from the third region (3) by a zone of the semiconductor layer (5) for creation of a depletion zone (9). The effect of the separation is to improve the gain of the device.