Electrical characterization of 4H–SiC avalanche photodiodes containing threading edge and screw dislocations

Abstract

The reverse voltage current characteristics and electroluminescence of small area 4H–SiC avalanche photodiodes were investigated and correlated with the presence of threading screw and edge dislocations. Localized electroluminescence was observed at threading dislocations at voltages close to breakdown whereas diodes without any extended defects exhibited uniform light emission in the active area. Diodes containing either edge or screw dislocations were found to have excess leakage currents and breakdown prematurely compared to diodes without dislocations.