A Lateral Power p-Channel Trench MOSFET Improved by Variation Vertical Doping

An improved lateral power p-channel trench metal-oxide-semiconductor field-effect transistor (MOSFET) is proposed. By using a technique of variation vertical doping (VVD), the threat of charge imbalance posted by the parasitic trench capacitance is eliminated. Moreover, a p-type VVD increases the number of carriers, and an n-type VVD intensifies the charge compensation effect. Hence, compared to the conventional device without VVD, the proposed device gets a significantly improved tradeoff relationship between the breakdown voltage (BV) and the specific ON-resistance ( R _ON,SP ). According to the simulation results, the proposed device using the triple piecewise VVD obtains a R _ON,SP of 10.6 mΩ·cm ² at a BV of 440 V, reaching a figure of merit (FOM = BV ² /R _ON,SP ) being 2.4 times larger than that of the prior art.