Novel Bulk Homogenization Field Devices with Reducing Process Difficulty

A novel bulk periodic modulation mechanism for homogenization field (HOF) device is proposed and experimentally demonstrated in this letter. The HOF structure introduces periodic negative charges at the bottom of each discrete MIS trench, providing an additional negative charge field modulation in the bulk of the device. The periodic modulation leads to increased bulk doping dose for lower specific on-resistance R on,sp . Based on the new mechanism, a design formula of the optimized modulation is deduced by considering the charge balances among the periodic charges, ionized donors in the drift and ionized acceptors in the P-sub, simultaneously. Experiments demonstrate that the HOF device with the bulk periodic modulation achieves reduced process difficulty, resulting in a 54.2% reduction in trench depth and exhibits a 14.8% reduction in R on,sp at a breakdown voltage V B of 679.5 V when compared with the reported HOF device.