Avalanche photodiode having a multiplication layer with superlattice

摘要

An avalanche photodiode in which a strained superlattice structure is used as a multiplication layer, comprising: an n+ type InP substrate; an n+ type InP epitaxial layer formed on a main surface of the substrate; an N type In1-xAlxAs layer formed on the epitaxial layer; an n+ type In1-xAlxAs layer formed on the N type In1-xAlxAs layer, the n+ type In1-xAlxAs layer having a relatively high impurity concentration more than the N type In1-xAlxAs layer; the multiplication layer deposited on the n+ type In1-xAlxAs layer, the multiplication layer having an In0.53Ga0.47As/In1-xAlxAs superlattice structure; first and second p+ type In1-xAlxAs layers laminated sequentially on the multiplication layer; an absorbing layer formed on the second p+ type In1-xAlxAs layer, the absorbing layer being made of an In0.53Ga0.47As; a P type InP layer formed on the absorbing layer to reduce a surface leakage current; an In0.53Ga0.47As layer formed on the P type InP layer to be provided for an ohmic contact, and metal layers formed on an upper surface of the In0.53Ga0.47As layer and the other surface of the substrate, respectively.