Coexistence of Space Charge Limited and Variable Range Hopping Conduction Mechanism in Sputter-Deposited Au/SiC Metal–Semiconductor–Metal Device

Abstract

Despite being the cornerstone of high-temperature and high-power applications, the fabrication of silicon carbide (SiC) thin films has been a major challenge among research activities related to wide bandgap semiconductors. As almost all the reported SiC thin films produced by RF sputtering are amorphous, the growth of crystalline thin film on p-type silicon substrate at high temperature (>900 °C) is presented in this work. A metal–semiconductor–metal (MSM) device is fabricated with gold (Au) electrodes by sputtering. A unique behavior of current–voltage ( I – V ) characteristics is found in different voltage regimes. The thermionic emission model fails to explain the observed I – V characteristics. To understand the current transport mechanism in detail, I – V characteristics are carried out in the temperature range 250–380 K and divided into two voltage regimes, below and above 1 V. Below 1 V, variable range hopping mechanism (VRH) is found to be dominant and above 1 V, and ohmic conduction followed by space charge limited conduction (SCLC) is held accountable for the current transport mechanism. The analysis of both mechanisms indicates the presence of disorder states and gives valuable information about trap centers. The C – V characteristics further suggest the presence of interface states and deep traps. The advantageous implementation of this information will help to design optoelectronic, magnetic, and efficient energy storage devices to extract the maximum performance.