P-type interface charge control layers for enabling GaN/SiC separate absorption and multiplication avalanche photodiodes

Abstract

A p-type interface charge control layer (PICCL) is introduced that enables optimization of the net positive polarization induced interface charge at the GaN/SiC interface in GaN/SiC separate absorption and multiplication avalanche photodiodes (SAM-APDs) by varying its thickness. The response from SAM-APDs with PICCL thickness less than 10 nm has an anomalous shape at all bias attributed to the collection of carriers generated directly in the SiC layer. Devices with a 15 nm thick PICCL exhibit GaN related response at high bias that is indicative of punch-through of the electric field into the GaN absorption region due to optimization of the net interface charge.