Patent ID: 8269303

Claim:
A SiGe photodiode, which is a p-i-n type photodiode composed of a Si x Ge 1-x semiconductor absorption layer, an upper electrode layer provided on the top face thereof, and a lower electrode layer provided under the rear face thereof, wherein the p-i-n type photodiode has a structure in which the Si x Ge 1-x semiconductor absorption layer is embedded in a groove formed in a part of a Si layer, and which comprises: a p-type or n-type doped lower electrode layer which is formed in a lower section of the groove; a layered structure composed of, a Si semiconductor layer and a SiGe buffer layer, which structure is formed on the lower section and the side wall of the groove; the Si x Ge 1-x semiconductor absorption layer which is formed on the layered structure; and a n-type or p-type doped upper electrode layer which is formed in an upper section of the groove.