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

Abstract

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 plasma-chemical 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.