Imaging systems with backside illuminated near infrared imaging pixels

Patent metadata

Field	Value
Publication number	US-9105546-B2
Application number	US-201313954844-A
Country	US
Kind code	B2
Filing date	Jul 30, 2013
Priority date	Sep 19, 2012
Publication date	Aug 11, 2015
Grant date	Aug 11, 2015

Abstract

An imaging system may include an image sensor having backside illuminated near infrared image sensor pixels. Each pixel may be formed in a graded epitaxial substrate layer such as a graded n-type epitaxial layer. Each pixel may be separated from an adjacent pixel by an isolation trench formed in the graded epitaxial layer. The isolation trench may be a continuous isolation trench or may be formed from a combined front side isolation trench and backside isolation trench that are separated by a wall structure. A buried front side reflector may be provided that reflects light such as infrared light that has passed through a pixel back into the pixel, thereby effectively doubling the silicon absorption depth of the pixels.

First claim

What is claimed is:

1. An image sensor, comprising:
a graded n-type epitaxial substrate layer;
a plurality of photodiodes formed in the graded n-type epitaxial substrate layer;
a plurality of isolation trenches in the graded n-type epitaxial substrate layer that separate adjacent photodiodes;
a reflective layer; and
a dielectric stack on the reflective layer, wherein the reflective layer is interposed between the plurality of photodiodes and the dielectric stack.…

Assignees

• Semiconductor Components Ind

Inventors

• Velichko Sergey
• Agranov Gennadiy

Classifications

• H10F39/8067

  Electricity · mapped topic

• H10F39/8063

  Electricity · mapped topic

• H10F39/807

  Electricity · mapped topic

• H10F39/014

  Electricity · mapped topic

• H10F39/011

  Electricity · mapped topic