High-density trench DMOSFETs employing two step trench techniques and trench contact structure

A novel process technique for fabricating trench DMOSFETs using 3 mask layers (trench, poly, metal), two step trench technique, and trench contact structure is realized in order to obtain cost-effective production capability, higher cell density, and better leakage characteristics. A unit cell with a cell pitch of 1.6 /spl mu/m and a channel density of 130Mcell/in/sup 2/ are obtained. The specific on-resistance was 0.28m/spl Omega/-cm/sup 2/ with a blocking voltage of 43 V.