Ultra-low specific on-resistance vertical double-diffused metal - Oxide semiconductor with a high-k dielectric-filled extended trench

An ultra-low specific on-resistance trench gate vertical double-diffused metal-oxide semiconductor with a high-k dielectric-filled extended trench (HK TG VDMOS) is proposed in this paper. The HK TG VDMOS features a high-k (HK) trench below the trench gate. Firstly, the extended HK trench not only causes an assistant depletion of the n-drift region, but also optimizes the electric field, which therefore reduces Ron,sp and increases the breakdown voltage (BV). Secondly, the extended HK trench weakens the sensitivity of BV to the n-drift doping concentration. Thirdly, compared with the superjunction (SJ) vertical double-diffused metal-oxide semiconductor (VDMOS), the new device is simplified in fabrication by etching and filling the extended trench. The HK TG VDMOS with BV = 172 V and Ron,sp = 0.85 mΩcm2 is obtained by simulation; its Ron,sp is reduced by 67% and 40% and its BV is increased by about 15% and 5%, in comparison with those of the conventional trench gate VDMOS (TG VDMOS) and conventional superjunction trench gate VDMOS(SJ TG CDMOS).