Electrical Properties of Evaporated Molybdenum Oxide Films

Abstract

Thin film capacitors of MoO₃ are found to be extremely temperature and frequency dependent. Changes in capacitance are reported as high as 60:1 over a temperature range of 100°C (at constant frequency) and over a two‐decade frequency range (at constant temperature). At lower temperatures and higher frequencies the capacitance corresponds to the geometric capacitance, but at higher temperatures and lower frequencies the capacitance is independent of the film thickness. Conductance and quality factor of the films are also observed to be extremely frequency and temperature sensitive. The results are explained in terms of Schottky barriers existing at the metal‐insulator interfaces, which arise due to the autodoping of the insulator, occurring during deposition of the films, by excess molybdenum. Excellent agreement is found to exist between the experimental data and the theory developed in the previous paper, and this correlation permits determination of the doping density (≃10¹⁸ cm⁻³), the donor depth (≃0.27 eV), and the width of the Schottky barriers (≃160 Å), among other properties of the films.