<Emphasis Type="Italic">Ex Situ</Emphasis> Thermal Cycle Annealing of Molecular Beam Epitaxy Grown HgCdTe/Si Layers

We present the results of ex situ thermal cycle annealing (TCA) of molecular beam epitaxy grown mercury cadmium telluride (HgCdTe) on Cd(Se)Te/Si(211) composite substrates. We examined the variation in the etch pit density (EPD) and overall crystalline quality with respect to annealing temperature, number of annealing cycles, total annealing time, pre-annealed EPD/crystal quality, buffer layer quality, and buffer layer lattice constant. Using TCA we observed an order of magnitude reduction in the dislocation density of the HgCdTe layers and a corresponding decrease in x-ray full width at half maximum, when the as-grown layer EPD was on the order of 1 × 10⁷ cm⁻². Among all the parameters studied, the one with the greatest influence on reducing EPD was the number of annealing cycles. We also noticed a saturation point where the HgCdTe/Si EPD did not decrease below ∼1 × 10⁶ cm⁻², regardless of further TCA treatment or the as-grown EPD value.