Patent ID: 8357960

Claim:
A photodiode comprising: a first metal contact; a semiconductor substrate of a first conductivity type, buffer layer of said first conductivity type, an absorption region electrically connected to said first metal contact, wherein said absorption region comprises a plurality of pillars, wherein said absorption region has a cross-sectional area of less than 25 square micrometers, and each said pillar includes a charge separation junction, and wherein said pillars are arranged in an array either randomly or with a certain pitch; and a second metal contact electrically connected to said absorption region, wherein said first metal contact is connected to said semiconductor substrate or said buffer layer, and wherein each said pillar comprises: at least one In-based layer of said first conductivity type, same conductivity type as said buffer layer and said semiconductor substrate; at least one InGaAs absorption layer; and at least one In-based layer of a second conductivity type opposite to said first conductivity type.