SPECIFIC CONTACT RESISTANCE OF INDIUM OHMIC CONTACTS TO N-TYPE HG1-XCDXTE

The specific contact resistant rho(C) of In contacts to n-Hg1-xCdxTe has been measured as a function of the Cd mole fraction and annealing treatment of the Hg1-xCdxTe. Transmission line model measurements were performed on the In/Hg1-xCdxTe junctions with the Hg1-xCdxTe doped n type in the range 3.5 X 10(16) to 1.6 X 10(18) cm-3 (77 K). A linear dependence of In rho(C) on x was obtained, with values of rho(C) ranging from 2.0 X 10(-5) OMEGA cm2 at x = 0.30 through to 2.6 X 10(-2) OMEGA cm2 at x = 0.68. Hg annealing of the epitaxial Hg0.38Cd0.62Te layers resulted in a decrease in rho(C) from 5.9 X 10(-3) cm2 unannealed to 1.2 X 10(-3) OMEGA cm2 after a 300-degrees-C anneal, corresponding to equivalent changes in the resistivity of the Hg1-xCdxTe. Isothermal annealing of the In/n-Hg1-xCdxTe contacts for x = 0.30, 0.40, and 0.62 produced an enhanced indiffusion of In but with only a minor reduction in rho(C).