A new buried-gate VMOSFET with suppressed overlap capacitance and improved electrical characteristics

This study presents a new buried-gate vertical MOSFET (BGVMOS) with suppressed overlap capacitance and improved electrical characteristics due to its modified gate structure. According to the TCAD simulations, our proposed BGVMOS structure can gain reduced parasitic capacitances (27.11% C_gd and 37.53% C_gs at V_Ds = 1.0 V), improved drain saturation current, and free kink effect, in comparison to a conventional VMOS (CVMOS) structure. Most importantly, the reduced surface scattering in the BGVMOS helps improve the drain current and the transconductance mainly owing to the 1/4 circle gate scheme which is difficult task for a CVMOS transistor.