Study on HK-VDMOS with Deep Trench Termination

A structure of junction edge termination for the High-K Vertical Diffused Metal Oxide Silicon (HK-VDMOS) is proposed and studied. It consists of two deep trenches filled with SiO2 and HK dielectric, respectively. The former is mainly used to sustain the surface high voltage, which significantly contributes to reduce the termination width. The latter transmits the strong electric field in the SiO2 into the source electrode before it reaches the inside HK-VDMOS cells, which ensures the optimized electric field distribution of the inside HK-VDMOS cells is not affected. Therefore, for the total device with termination, high breakdown voltage and ultralow specific on-resistance as well as very small termination width can be simultaneously obtained. Numerical simulation shows that, for an N-type HK-VDMOS (the permittivity is set as K = 300) with the proposed termination, the Ron,sp of 26.4 mΩ cm2 is achieved at a breakdown voltage of 743 V, where the termination width is only 14 μm.