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 Q_O 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 D_it obtained by Nicollian–Brews conductance method is lower in the structure based on the PVT grown sample.