The Effect of Nitrogen Plasma Treatment Process on Ohmic Contact Formation to N-Type 4H-SiC

Abstract

In this work, a nitrogen plasma treatment process was employed on n-type 4H-SiC. Both the Si- and C-face were studied and treated with N2 plasma. The surface concentration of nitrogen increased from 5×1018 cm-3 to 5×1021 cm-3 in both the Si-face and C-face as analyzed by secondary ion mass spectroscopy (SIMS). This shows that a simple plasma treatment process was able to incorporate very high concentration of nitrogen dopants otherwise done using high temperature implanters. Titanium-based Ohmic contacts were formed at ~800 °C thanks to the presence of high concentration nitrogen dopants. Specific contact resistance of (ρc ~1.5 × 10-6 Ω.cm2 and ~1.9 × 10-6 Ω.cm2) was obtained on Si-face and C-face, respectively.