Investigation of the characteristics of the low voltage trench-gated power MOSFET with the trench body contact

A low voltage trench-gated power MOSFET (U-MOSFET) with the trench body contact is investigated in this paper. We find that DC characteristics and AC characteristics will be changed by increasing the width and the depth of the trench body contact. The simulation results show that the changes of width and depth of trench body contact make a larger impact on AC characteristics than DC characteristics. It is obvious that the gate-drain capacitance (C_GD) decreases and the capacitance (C_DS) coupling the drain to the source increases when the depth and the width of trench body contact extend. When the depth and half width increase from 0.8 μm to 1.0 μm and from 0.125 μm to 0.275 μm respectively, the breakdown voltage ranges from 21.6V to 17.9V. In the meantime, the input capacitance C_ISS (C_GD plus C_GS) and the output capacitance C_OSS (C_GD plus C_DS) have increased by at most 4% and ±10% respectively, but the feedback capacitance C_RSS (C_GD) is reduced by 25.9% at least. Therefore, the feedback between the gate and drain decreased leading to improve the switching performance of the power MOSFET.