Design and research of medium voltage trench MOSFET

Based on simulation and experimental methods, the design and research of 100VN trench MOSFET is carried out. Through the trench depth, body dose and gate oxide thickness experiment, the effects on breakdown voltage, threshold voltage and on-resistance are obtained and the mechanism is analyzed. The current path inside the device and the distribution of impact ionization rate can be seen through the simulation. As the trench depth increases, the breakdown voltage first increases and then decreases, and the on-resistance shows an opposite trend; the breakdown voltage has a weak correlation with the implant dose, and the threshold voltage increases with the increase of the implant dose; the breakdown voltage increases with the gate oxide thickness increases, but the change range is not large, and the threshold voltage has a strong correlation with the thickness changes. Through gradual optimization, the final structure and process parameters are obtained as trench depth is 1.5 μm, body dose is 1.3E13, gate oxide thickness is 700 A and the device final electrical parameters are obtained by real tape-out. Finally, we can get the breakdown voltage is 105.6 V, threshold voltage is 2.67 V and on-resistance is 3.12 mR. Compared with the simulation results, the change rates are 98%, 94% and 75% respectively.