Evaluation of MOS structures processed on 4H-SiC layers grown by PVT epitaxy

MOS capacitors have been fabricated on 4H-SiC epilayers grown by physical vapor transport (PVT) epitaxy. The properties were compared with those on similar structures based on chemical vapor deposition (CVD) layers. Capacitance-voltage (C-V) and conductance measurements (G-V) were performed in the frequency range of 1 kHz to 1 MHz and also at temperatures up to 475 K. Detailed investigations of the PVT structures indicate a stable behaviour of the interface traps from room temperature up to 475 K. The amount of positive oxide charge QO is 6.83 × 109 cm−2 at room temperature and decreases with temperature increase. This suggests that the processed devices are temperature stable. The density of interface states Dit obtained by Nicollian-Brews conductance method is lower in the structure based on the PVT grown sample.