Deposition of high quality silicon dioxide on Hg_1-xCd_xTe by low-temperature liquid phase deposition method

A low temperature (35-45°C) process of liquid phase deposition (LPD) for the growth of silicon dioxide (SiO₂) on Hg_1-xCd_xTe is proposed. To enhance the formation of SiO₂, the HgCdTe surface has to be treated by ammonia solution before LPD. A thin native oxide which is formed by previous surface treatment involving OH^- radicals greatly enhances the SiO₂ deposition on HgCdTe. Thus, SiO₂ films with a high refractive index (1.465) and a low p-etching rate (34 Å/s) were obtained. Auger electron spectroscopy depth profile shows less interdiffusion of constituent atoms between the SiO₂ layer and the HgCdTe substrate. Electrical properties of the SiO₂/p-HgCdTe interface are also characterized at 77 K. It is found that the p-HgCdTe surface is accumulated and the effective surface charge density is estimated to be -2.25×10¹⁰ cm^-2. The leakage current and dielectric breakdown strength are also found to be 0.356 nA (at -5 V) and above 650 KV/cm, respectively. Furthermore, the growth mechanism of LPD-SiO₂ on HgCdTe is proposed.