STUDIES OF AU OHMIC CONTACTS TO P-TYPE HG1-XCDXTE

Electroless Au contacts to p-type Hg1-xCdxTe in many cases exhibit ohmic behavior. Our investigation of the interfacial chemistry of such contacts suggest that this ohmic behavior is due to the presence of a Te, O, and Cl layer. To test this hypothesis, thin plasma oxide layers were then used in evaporated Au contacts. Ohmic behavior was also observed for the annealed plasma oxidized contacts. We believe this ohmic behavior is primarily a result of the low interface state density at the interfacial layer/Hg1 xCdxTe interface and in addition, a 100 °C anneal promoted a further reduction in the interface state density and thus lowered the contact resistance. In comparison, as-deposited and annealed Au contacts without a thin interfacial layer were rectifying with a large barrier height. © 1990, American Vacuum Society. All rights reserved.