The effect of off-axis Si (100) substrates on the defect structure and electrical properties of β-SiC thin films

Abstract

Antiphase domain-free, monocrystalline β-SiC thin films have been epitaxially grown on off-axis Si (100) substrates. The effects of degree of misorientation and substrate preannealing on the antiphase domain boundaries (APB's) have been investigated. Wet oxidation, optical microscopy, and transmission electron microscopy were used to characterize the defect structures in both β-SiC thin films grown on exact Si (100) and on off-axis Si (100) substrates. The results revealed that many dislocations were included in APB's and that APB's were eliminated in the β-SiC thin films grown on Si (100) substrates that were oriented 2°–4° from [100] toward the [011] direction. Some APB's were observed near the edge of the β-SiC film on the 2° off-axis Si (100) substrates; however, they were eliminated by substrate preannealing. The carrier concentration and electron mobility of these β-SiC films were similar to those of β-SiC films grown on exact Si (100) substrates as determined by differential capacitance-voltage and Hall effect measurements. Au-β-SiC Schottky diodes were also fabricated on the β-SiC thin films on 4° off-axis substrates and had an ideality factor of 1.4. Differential capacitance-voltage measurements and current-voltage characteristics of Au-β-SiC Schottky diodes indicated that APB's caused significant leakage current in the β-SiC thin films.