US 2004/0164321 A1 · Vertical charge transfer active pixel sensor

Abstract

An active pixel sensor comprising an N well of n type silicon formed in a p type silicon substrate and a P well of p type silicon is formed in the N well. A deep N well is formed of n type silicon underneath the P well. The edges of the deep N well contact the bottom of the N well forming an overlap region which can either be not depleted of charge carriers thereby electrically connecting the N well to the deep N well or depleted of charge carriers thereby electrically isolating the N well from the deep N well. N regions formed in the P well and P regions formed in the N well are used to reset the pixel and to read the pixel after a charge integration period. An array of P wells formed within N wells can be used to form an array of active pixel sensors. In this array an overlap region is formed between each N well and the deep N well. In an array of active pixel sensors the N regions can be binned together by using the overlap regions to connect each N well to the deep N well thereby achieving noise suppression during the reset cycle.

Claims34

Dependent claims

An active pixel sensor, comprising:

a p type epitaxial silicon substrate;
an N well formed in said substrate;
a P well formed in said N well;
a deep N well formed in said substrate beneath said P well;
an overlap region formed between said N well and said deep N well wherein said overlap region electrically connects said N well to said deep N well when said overlap region is not depleted of charge carriers and electrically isolates said N well from said deep N well when said overlap region is depleted of charge carriers;
a first N region and a second N region formed in said P well;
and
a P region formed in said N well.

5 more elements

Dependencies are inferred from the claim text.

Vertical charge transfer active pixel sensor

Life of this patent

Vertical charge transfer active pixel sensor

Life of this patent

Abstract

Claims34