A novel process technique for fabricating high reliable trench DMOSFETs using self-align technique and hydrogen annealing

摘要

A novel process technique for fabricating trench DMOSFETs using 3 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 /spl mu/m and a channel density of 100 Mcell/in/sup 2/ are obtained. Specific on-resistance is 0.36 m/spl Omega/.cm/sup 2/ with a blocking voltage of 43 V. The time to breakdown of gate oxide grown on the hydrogen annealed trench surface is much longer than that of the gate oxide grown on the non-hydrogen annealed trench surface.