METHOD FOR FORMING PINNED PHOTO DIODE OF CMOS IMAGE SENSOR

摘要

PURPOSE: A method for forming a pinned photo diode of a CMOS(Complementary Metal Oxide Semiconductor) image sensor is provided to be capable of improving the operation of the pinned photo diode. CONSTITUTION: A photo diode(11) is formed at the upper portion of a P type substrate(18). The first N+ type potential well(17a) is formed between the p type substrate and the photo diode. The second N+ type potential well(17b) is formed at the peripheral region of the photo diode. At this time, the second N+ type potential well has a larger depth than that of the first N+ type potential well. Preferably, excess electrons generated from the first N+ type potential well, are moved to the second N+ type potential well by light.