Method of manufacturing photodiode CMOS image sensor

Abstract

A method for manufacturing a photodiode CMOS image sensor. A first well and a second well are formed in a first type substrate. An isolation layer is formed over the first well and the second well. At the same time, an isolation layer is formed over another region to pattern out an active region for forming the photodiode. A protective ring layer is formed over the peripheral area of the photodiode active region. A first gate structure and a second gate structure are formed above the first well and the second well respectively. A first type source/drain region and a second type source/drain region are formed in the first well and the second well respectively. Concurrently, a second type heavily doped layer is formed in the first type substrate inside the area enclosed by the protective ring layer. A high-energy ion implantation is carried out to form a second type lightly doped layer in the first type substrate just outside the second type heavily doped layer. The second type lightly doped layer has a thickness much greater than the second type heavily doped layer.

Dependencies are inferred from the claim text.