Ohmic contacts of 4H-SiC on ion-implantation layers

The ohmic contacts of 4H-SiC are fabricated on nitrogen ion implanted layers made by performing box-like-profile implantation three and four times. Implantation parameters such as the standard deviation σ and the projection range R_p are calculated by the Monte Carlo simulator TRIM. Ni/Cr ohmic contacts on Si-face 4H-SiC implantation layers are measured by transfer length methods (TLMs). The results show that the values of sheet resistance R_sh are 30 kΩ /□ and 4.9 kΩ/□ and the values of specific contact resistance \rho_\rm c of ohmic contacts are 7.1× 10^-4 Ω\cdotcm² and 9.5 × 10^-5Ω \cdot cm² for the implanted layers with implantation performed three and four times respectively.