Buried Gate Static Induction Transistors in 4H-SiC (SiC-BGSITs) with Ultra Low On-Resistance

Ultra low on-resistance silicon carbide static induction transistors with buried gate structures (SiC-BGSITs) have been successfully developed. A submicron buried p⁺ gate structure was fabricated by the combination of submicron trench dry etching and epitaxial growth on a trench structure. A drain current I_DS reached 8A at a drain voltage V_DS = 1 V, corresponding to a specific on-resistance R_onS of 1.1mΩ·cm² at a current density J_D =200 A/cm², in the BGSIT with the channel width W_ch of 0.9 μm. A breakdown voltage V_BR was ~700 V at a negative gate bias V_G = -12 V. A clear saturation I_DS-V_DS characteristic and slightly high R_onS(1.4mΩ·²) were observed in the BGSIT with narrow W_ch of 0.7 μm. R_onS increased in proportion to T^2·3 in any channel width due to enhanced phonon scattering.