CMOS image sensor including superlattice to enhance infrared light absorption

US10276625B1 · kind B1 · utility

Assignee

• ATOMERA INCORPORATED · US

Inventors

• Robert J. Mears · Wellesley, US
• Marek Hytha · Brookline, US

Key dates

• Filing date: Dec 15, 2017
• Grant date: Apr 30, 2019
• Expiry date: Dec 15, 2037

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F39/8063

Abstract

A CMOS image sensor may include a semiconductor substrate having a first conductivity type, and a plurality of laterally adjacent infrared (IR) photodiode structures on the substrate. Each IR photodiode structure may include a superlattice on the semiconductor substrate including a plurality of stacked groups of layers, with each group of layers including a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. Further, the superlattice may have the first conductivity type. The CMOS image sensor may further include a semiconductor layer on the superlattice, a retrograde well extending downward into the semiconductor layer from a surface thereof and having a second conductivity type, a first well around a periphery of the retrograde well having the first conductivity type, and a second well within the retrograde well having the first conductivity type.