A highly reliable trench DMOSFET employing self-align technique and hydrogen annealing

A novel process technique for fabricating trench double diffused MOSFETs (DMOSFET) using three mask layers is realized in order to obtain cost-effective production capability, higher cell density and current driving capability, and higher reliability. A unit cell with a cell pitch of 2.3/spl sim/2.4 μm and a channel density of 100 Mcell/in
²
are obtained. Specific on-resistance is 0.36 m/spl Omega/.cm
²
is obtained with a blocking voltage of 43 V. The highly reliable trench DMOSFET was obtained by the formation of the corner rounding of the hydrogen annealed trench surface.