Current transport mechanisms of Ge/sub 1-y/C/sub y//Si heterojunction diodes

Alloys of group IV semiconductors have attracted more and more attention recently as a material for use in the development of Si-based heterostructure devices. In this paper, the current transport mechanisms of relaxed p-type Ge/sub 1-y/C/sub y/ alloy films on n-type Si at both forward and reverse bias were studied. The current transport is dominated by combined thermal injection, defect tunneling, and recombination mechanisms. The presence of carbon reduces interface states, decreases the leakage current, and increases forward turn-on voltage. This paper demonstrates the benefits of alloying C into Ge and the promising characteristics of Ge/sub 1-y/C/sub y//Si heterostructure devices for future electronic and optoelectronic applications.