Fabrication of a high-precision blooming control structure for an image sensor

US7074639B2 · kind B2 · utility

Assignee

• Massachusetts Institute of Technology · US

Inventors

• Barry E. Burke · Spring, US
• Eugene D. Savoye · Concord, US

Key dates

• Filing date: Dec 17, 2001
• Grant date: Jul 11, 2006
• Expiry date: Jul 31, 2024

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F39/158

Abstract

Provided is a method of fabrication of a blooming control structure for an imager. The structure is produced in a semiconductor substrate in which is configured an electrical charge collection region. The electrical charge collection region is configured to accumulate electrical charge that is photogenerated in the substrate, up to a characteristic charge collection capacity. A blooming drain region is configured in the substrate laterally spaced from the charge collection region. The blooming drain region includes an extended path of a conductivity type and level that are selected for conducting charge in excess of the characteristic charge collection capacity away from the charge collection region. A blooming barrier region is configured in the substrate to be adjacent to and laterally spacing the charge collection and blooming drain regions by a blooming barrier width. This barrier width corresponds to an acute blooming barrier impurity implantation angle with the substrate. The blooming barrier region is of a conductivity type and level that is selected based on the blooming barrier width to produce a corresponding electrical potential barrier between the charge collection and …