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

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 N 2 plasma. The surface concentration of nitrogen increased from 5×10 18 cm -3 to 5×10 21 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 (ρ c ~1.5 × 10 -6 Ω.cm 2 and ~1.9 × 10 -6 Ω.cm 2 ) was obtained on Si-face and C-face, respectively.