Assessing the electrical properties of cubic silicon carbide by mercury probe measurements

Abstract

This study outlines the effectiveness of mercury (Hg) probe measurements in evaluating the net carrier concentration of 3C-SiC epilayers and their barrier height evaluating their performance for device fabrication. Both mercury probe current voltage (Hg IV) and mercury probe capacitance voltage (Hg CV) measurements are compared to Schottky Barrier Diode (SBD) IVs and CVs, respectively. Increasing Schottky Barrier Height (SBH) with decreasing carrier concentration was observed when increasing the 3C-SiC thickness from 3 μm to 8 μm. Subsequently, this measurement is implemented for evaluating carrier concentration of 3C-SiC epilayers whilst varying C/Si ratios during growth to demonstrate the lowest non-intentionally doped carrier concentrations down to value of ∼5 × 10 15 cm −3 for a C/Si ratio between 1.3 and 1.4. This trend is compared to the crystal quality of the 3C-SiC layers, by high resolution x-ray diffraction achieving the best Full Width Half Maximum (FWHM) of the diffracted peak of 0.29°, with a strong correlation between Hg CV carrier concentration, Schottky barrier height (SBH) and FWHM values.