Influence of the n-diffusion layer on the channel current and the breakdown voltage in 4H-SiC SIT

For a recessed gate (RG) silicon carbide (SiC) static induction transistor (SIT), an n-diffusion layer technique to maximize a maximum channel current (I_MAX) and realize an efficient breakdown voltage (BV) was presented. An n-diffusion layer having a doping profile of a Gaussian distribution was formed from the source to the channel region and introduced to elevate the doping concentration of the channel region. Through the simulation of a RG SiC SIT with an n-diffusion layer, it was verified that an n-diffusion layer technique was an excellent way to realize a very small width of a source region (W_s), resulting in an larger I_MAX and a higher BV simultaneously, and it was desirable to employ an n-diffusion layer having a slightly larger junction depth (X_j) than the depth of a gate trench (L_T)(L_T < X_j < 1.3L_T) into a RG SiC SIT with a small width of the source region (W_s ≈ 0.5 μm).