Study of indium antimonide metal-oxide-semiconductor structure prepared by direct photochemical-vapor deposition

Abstract

Silicon dioxide (SiO2) insulator layers on indium antimonide (InSb) have been prepared by direct photochemical-vapor deposition at low temperature below 200 °C using 2537 Å UV light. Ellipsometric studies prove that the refractive index and deposition rate of the photo-oxide films depend on the substrate temperature and gas ratio. The films evaluated by Auger electron spectroscopy (AES) depth profile showed that composition atoms were distributed uniformly throughout the oxide film. The AES analysis found the dominant components of the oxide film are silicon and oxygen. Fourier transform infrared spectroscopy absorption shows that the grown film has strong Si—O bonds with few Si—H bonds. The chemical x-ray photoelectron spectroscopy depth profile shows that the constituents of the semiconductors’ outdiffusion into the oxide are few. Metal-oxide-semiconductor (MOS) capacitors were constructed on InSb substrates. Capacitance voltage (C-V) characteristics of the MOS capacitors were measured at 77 K. The interface-state density is of the order of 1011 cm−2 eV−1, and distributed in a very good U shape within the midgap. C-V curves showed almost no hysteresis and smaller flatband voltage. The current-voltage curve shows the leakage current is about 1 nA at 0.8 V, and the breakdown voltage is about 0.8 MV/cm.