4H-SiC trench MOSFETs based on multilayer epitaxial structures

The 4H-SiC trench MOSFETs based on multilayer epitaxial structures (N+/P-/N-) were demonstrated in this paper. N+/P-/N- multiple epitaxial layers were continuously grown on 3-inch N+ type 4H-SiC substrate by chemical vapor deposition (CVD). Trench gate was fabricated by using a controlled ICP etch process. The ion implantation and following high temperature activation anneal were avoided throughout the entire fabrication process. The measured threshold voltage (V
_th
) is 5.2V by linear extrapolation from the transfer characteristics. The device shows a maximum breakdown voltage of 950V (I
_DS
=90μA@950V) at Vg=0V and on-state source-drain maximum output current is 350mA at V
_g
=40V and V
_DS
=20V that corresponds to a specific on-resistance is 68mΩ·cm
²
.