Chemical vapor deposition and characterization of 6H-SiC thin films on off-axis 6H-SiC substrates

Abstract

High-quality, monocrystalline 6H-SiC thin films have been epitaxially grown on 6H-SiC {0001} substrates which were prepared 3° off-axis from 〈0001〉 towards 〈112̄0〉 at 1773 K via chemical vapor deposition (CVD). Essentially, no defects were generated from the epilayer/substrate interface as determined by cross-sectional transmission electron microscopy (XTEM). Double positioning boundaries which were observed in β-SiC grown on 6H-SiC substrates were eliminated as confirmed by plan-view TEM. A strong dependence of the surface morphology of the as-grown thin films on the tilting orientation of the substrates was observed and reasons for this phenomenon are discussed. The unintentionally doped 6H-SiC thin films always exhibit n-type conduction with a carrier concentration on the order of 1016 cm−3. Au-6H-SiC Schottky barrier diodes were fabricated on the CVD 6H-SiC thin films and it was found that the leakage current at a reverse bias of 55 V was only 3.2×10−5 A/cm2. This is compared to SiC films grown on other substrates.