Preparation of PbTe Thin Films for High-Sensitive Mid-IR Photodetectors by PECVD

Lead telluride (PbTe) possesses a good performance as a thermoelectric material due to both a low thermal conductivity and its electrical properties. It has peak thermoelectric characteristics at high temperature and is widely used in spacecraft power applications and as a waveguide-integrated detector monolithically integrated on a silicon substrate and operating at room temperature. In this work PbTe thin films were prepared via direct plasma-chemical interaction of lead and tellurium vapors. Argon of high purity was also used as a career gas for precursors transport to the plasma zone and as a plasma feed gas. The process was carried out at the low pressure (0.01 Torr) in inductively coupled non-equilibrium RF (40.68 MHz) plasma discharge. Optical emission spectroscopy (OES) was used to identify the exited species and to assume the possible mechanisms of plasmachemical reactions. The stoichiometry, structure and morphology of the surface of the materials obtained was also studied by deferent analytical techniques dependently on the conditions of the plasma process.