Group iii-v compound semiconductor photo detector, method of fabricating group iii-v compound semiconductor photo detector, photo detector, and epitaxial wafer

Abstract

An object of the present invention is to provide a group III-V compound semiconductor photo detector comprising an absorption layer having a group III-V compound semiconductor layer containing Sb as a group V constituent element, and an n-type InP window layer, resulting in reduced dark current. The InP layer 23 grown on the absorption layer 23 contains antimony as impurity, due to the memory effect with antimony which is supplied during the growth of a GaAsSb layer of the absorption layer 21 . In the group III-V compound semiconductor photo detector 11 , the InP layer 23 contains antimony as impurity and is doped with silicon as n-type dopant. Although antimony impurities in the InP layer 23 generate holes, the silicon contained in the InP layer 23 compensates for the generated carriers. As a result, the second portion 23 d of the InP layer 23 has sufficient n-type conductivity.

What is claimed is: 
     
         1 . A group III-V compound semiconductor photo detector comprising:
 a semiconductor substrate having a principal surface;   an absorption layer being disposed on the principal surface of the semiconductor substrate; and   an InP layer being disposed on the absorption layer,   the bandgap energy of the absorption layer being smaller than the bandgap energy of InP,   the InP layer being doped with donor, and   the concentration of donor in the InP layer being not less than 1×10 16  cm −3 .   
     
     
         2 . The group III-V compound semiconductor photo detector according to  claim 1 , wherein the concentration of donor in the InP layer is not more than 1×10 19  cm −3 . 
     
     
         3 . The group III-V compound semiconductor photo detector according to  claim 1 , wherein the donor in the InP layer is silicon.