Patent ID: 9437644
Filing Date: 2016-09-06
CPC Classification: H01L,Y02E

Claim Text:
1. A semiconductor device, comprising: a semiconductor substrate having a main surface; a first p type epitaxial layer formed over the main surface; a second p type epitaxial layer formed to cover an upper surface of the first p type epitaxial layer; a first photoelectric conversion element formed in the second p type epitaxial layer; and a first p type impurity region formed in the second p type epitaxial layer, wherein the first and second p type epitaxial layers are each made of silicon, wherein the first p type epitaxial layer has a p type impurity concentration higher than that of the second p type epitaxial layer, and wherein the first p type impurity region has a p type impurity concentration different than that in the second p type epitaxial layer.