Deposition and characterization of cadmium telluride/cadmium telluride (111) growth by close-spaced sublimation (CSS)

Polycrystalline CdTe was grown on CdTe (111) using the Close-Spaced Sublimation (CSS) technique. A series of experiments were designed to determine the experimental parameters which would result in a low growth rate of approximately 1μm/hr, and the deposition of a high quality epilayer of CdTe onto single crystal CdTe (111) substrates using a close spaced sublimation reactor (CSS). The study was classified into five stages. The substrate surface cleaning/surface preparation was done using an etchant consisting of HNO3, H 3PO4 and DI water (1:70:29) in order to remove the native oxide and surface impurities. A smooth epitaxial layer was obtained at maximum ΔT values of 5°C between the source and substrate, and substrate temperatures of 550°C. A growth rate less than 1 μm/hr was achieved. The samples were characterized using optical microscope, scanning electron microscope (SEM) and an Alpha Step Profiler. Granular and planar films were obtained with pyramid/triangular features inherent in the growth process for both types of films