Low-temperature growth of CdTe thin films as passivation layers for IR and THz functional elements

Abstract

Low-temperature modes of growing thin (dCdTe = 80–360 nm) CdTe layers by the “hot-wall” method with a high degree of adhesion to CdHgTe epitaxial layers were implemented. Growth parameters (source and substrate temperatures 650 K and 373 K, respectively, deposition time 60 min), at which the film is optimal when used as a protective passivation coating for the functional elements of the IR and THz photoelectronics were selected. The study of morphology, chemical composition and electrical properties of CdTe thin films depending on temperature and growth time were carried out. It is shown that the CdTe semiconductor film on the CdHgTe surface grows in columns that aggregate with increasing deposition time. The study of capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics of CdTe/p-Si structures demonstrated the controllability of the space charge region in silicon by the voltage applied to CdTe, which indicates good dielectric properties of CdTe with low surface density at the CdTe/p-Si boundary (4.5 × 1010 сm−2) and small leakage currents through the dielectric.