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

A novel technique for fabricating high reliability trench DMOSFETs using three mask layers is realized to obtain cost-effective production capability, higher cell density and current driving capability, and higher reliability. This technique provides a unit cell with 2.3~2.4 (mu)m pitch and a channel density of 100 Mcell/in/sup 2/. Specific onresistance is 0.36 m(omega).cm/sup 2/ with a blocking voltage of 43 V at a gate voltage of 10 V and 5 A source-to-drain current. The time to breakdown of gate oxide grown on the hydrogen annealed trench surface is much longer than that of oxide grown on a nonhydrogen annealed trench surface.