CMOS image sensor including photodiodes with overlying superlattices to reduce crosstalk

US10355151B2 · kind B2 · utility

Assignee

• ATOMERA INCORPORATED · US

Inventors

• Yi-Ann Chen · Campbell, US
• Abid Husain · San Jose, US
• Hideki Takeuchi · Sakaki, JP

Key dates

• Filing date: Dec 15, 2017
• Grant date: Jul 16, 2019
• Expiry date: Dec 15, 2037

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10F39/807

Abstract

A CMOS image sensor may include a semiconductor substrate having a first conductivity type, and a plurality of laterally adjacent photodiodes formed in the substrate. Each photodiode may include a retrograde well extending downward into the substrate from a surface thereof and having a second conductivity type, a first well around a periphery of the retrograde well having the second conductivity type, and a second well within the retrograde well having the first conductivity type. Each photodiode may further include first and second superlattices respectively overlying each of the first and second wells. Each of the first and second superlattices may include 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.