Specific contact resistance of indium ohmic contacts to n-type Hg1−xCdxTe

Abstract

The specific contact resistant ρC of In contacts ton-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 3.5×1016 to 1.6×1018 cm−3 (77 K). A linear dependence of In ρC on x was obtained, with values of ρC ranging from 2.0×10−5 Ω cm2 at x=0.30 through to 2.6×10−2 Ω cm2 at x=0.68. Hg annealing of the epitaxial Hg0.38Cd0.62Te layers resulted in a decrease in ρC from 5.9×10−3 Ω cm2 unannealed to 1.2×10−3 Ω cm2 after a 300 °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 ρC.