Deposition of high quality silicon dioxide on Hg1-xCdxTe by low-temperature liquid phase deposition method

A low temperature (35-45 degrees C) process of liquid phase deposition (LPD ) for the growth of silicon dioxide (SiO2) on Hg1-xCdxTe is proposed. To en hance the formation of SiO2, the HgCdTe surface has to be treated by ammoni a solution before LPD. A thin native oxide which is formed by previous surf ace treatment involving OH- radicals greatly enhances the SiO2 deposition o n HgCdTe. Thus, SiO2 films with a high refractive index (1.465) and a low p -etching rate (34 Angstrom/s) were obtained. Auger electron spectroscopy de pth 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 su rface is accumulated and the effective surface charge density is estimated to be -2.25 x 10(10) cm(-2). The leakage current and dielectric breakdown s trength are also found to be 0.356 nA (at -5 V) and above 650 KV/cm, respec tively. Furthermore, the growth mechanism of LPD-SiO2 on HgCdTe is proposed . (C) 1999 American Vacuum Society. [S0734-2101(99)00701-0].