A Novel Diffusion Resistant P-Base Region Implantation for Accumulation Mode 4H–SiC Epi-Channel Field Effect Transistor

Abstract

A novel implantation technique using the carbon (C) and boron (B) sequential implantation is employed to control the B lateral and vertical diffusion from the p-base region of the planar silicon carbide (SiC) epi-channel field effect transistor (ECFET). The current deep level transient spectroscopy measurements were performed to establish the inter-correlation between the B enhanced diffusion and the electrically active defects introduced by the C and B sequential implantation. It was found that the formation of deep defect level is completely suppressed for the same ratio (C:B=10:1) as that for the B diffusion in 4H–SiC. A diffusion mechanism which is correlated to the formation of D center was proposed to account for the experimentally observed B enhanced diffusion. The effectiveness of C and B implantation technique in suppressing the junction field effect transistor (JFET) pinch effect is clearly visible from the 3–4 fold increase in drain current of fabricated 4H–SiC ECFET for p-base spacing which was scaled down to about 3 µm. This novel diffusion resistant implantation technique open doors for the larger packing densities through unit-cell pitch reduction for SiC high power device applications.