Method for making CMOS image sensor including photodiodes with overlying superlattices to reduce crosstalk

US10461118B2 · 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: Oct 29, 2019
• Expiry date: Jan 16, 2038

Classification

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

Abstract

A method for making a CMOS image sensor may include forming a plurality of laterally adjacent photodiodes on a semiconductor substrate having a first conductivity types by forming a retrograde well extending downward into the substrate from a surface thereof and having a second conductivity type, forming a first well around a periphery of the retrograde well also having the second conductivity type, and forming a second well within the retrograde well having the first conductivity type. Furthermore, first and second superlattices may be respectively formed overlying each of the first and second wells, with each of the first and second superlattices comprising a plurality of stacked groups of layers, and each group of layers comprising 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.