Patent ID: 7553690
Filing Date: 2009-06-30
Classification: H01L,Y02E

Abstract:
1. A method for manufacturing an avalanche photodiode, comprising: forming an absorber layer and an avalanche layer over a substrate, the avalanche layer including a centrally located active region having an outer edge; forming a patterned mask over a surface of the avalanche layer, the patterned mask including a plurality of floating concentric mask rings; forming a plurality of substantially concentric patterned rings inside, and substantially concentric with, an innermost floating mask ring such that the patterned rings and the innermost floating mask ring collectively define a plurality of openings, and the outer edge of the active region being positioned between the innermost floating mask ring and an outermost patterned ring; forming a charge layer beneath the avalanche layer; and depositing a dopant over the patterned mask, patterned rings and the avalanche layer such that the dopant diffuses into the avalanche layer in areas where an opening is defined, and the floating mask rings, and patterned rings being configured such that the depth to which the dopant diffuses into the avalanche layer varies so as to form a sloped diffusion front in the active region, and the sloped diffusion front including a plurality of diffusion lines, one of which is substantially linear and has a non-zero slope in the active region, and the substantially linear diffusion line extending from the outer edge of the active region to a center of the active region.