Split-gate Resurf Stepped Oxide (RSO) MOSFETs for 25V applications with record low gate-to-drain charge

This paper presents a split-gate version of the resurf stepped oxide (RSO) MOSFET. Splitting the gate enables a drastic reduction of the gate-to-drain capacitance intrinsic to the RSO device concept while keeping all the benefits of the RESURF effect. We achieved a record on- resistance of 3.8 mOmegamm² and gate-to-drain charge of 0.9 nC.mm^-2 at a breakdown voltage of 35 V for a pitch of 1.3 mum (0.8 mum trench width). The switching losses of our split-gate RSO MOSFET are 4 times better than the best published data in the same voltage range.