Low voltage TrenchMOS combining low specific R DS(on) and Q G FOM

Abstract

The combination of low specific on-resistance, Sp.R DS(on ), and low gate charge, Q G and Q GD , has been achieved by applying a superjunction approach to an n-type 30V vertical trench power MOSFET structure. Whereas lateral technologies have low Q G and Q GD figures of merit with poor Sp.R DS(on ) (due to cell pitch limitations) and split-gate RSO structures have excellent Sp.R DS(on) and Q GD FOM at the expense of the Q G FOM (due to creation of additional C GS ), the superjunction structure has been shown to be achieving benchmark performance in all three of these performance indicators simultaneously. For a 30V rated device, specific on-state resistances of 3.9mOmm2 (V GS =10V) and 6.5mΩmm2 (V GS =4.5V) have been demonstrated along with switching figures of merit as low as 22.7mΩnC (RDS(on)×QG) and 4.6mΩnC (R D S(on)×QGD). The result is a technology that combines the best aspects of both vertical trench and lateral power MOSFET structures.