Design and Fabrication of 4H-Sic Mosfets with Optimized JFET and p-Body Design

In this paper, 4H-SiC planar MOSFETs were designed and fabricated. By using TCAD tool, the trade-off between on-resistance and maximum gate oxide electric field was optimized. With optimized gate oxide growth process, the gate oxide’s critical electric field of 9.8 MV/cm and the effective barrier height of 2.57 eV between SiO2 and 4H-SiC were obtained. The field effective mobility with different p-body doping was compared and studied. The MOS interface state density of 1.12E12 cm-2eV-1 at EC - EIT = 0.21 eV and channel mobility of 19.3 cm2/Vs at VGS = 20 V were obtained. The fabricated MOSFET’s on-resistance of 6.4 mΩcm2 was obtained with hexagonal cell structure which is very consistent with the simulation results.