2.5 V-driven Nch 3rd generation trench gate MOSFET

We developed a 3rd generation trench gate MOSFET driven by a gate voltage of 2.5 V. The on-resistance (R_on) of the 3rd generation device has been reduced by 40% compared with the conventional (2nd generation) device, to the value of 12 mΩ maximum (at V_GS=2.5 V) by using certain techniques. In order to reduce the R_on value, it is necessary to thin the epitaxial layer and shrink the chip size. In order to thin the epitaxial layer, it is important to control trench depth exactly to maintain the drain-source breakdown voltage (V_DSS). This is done by using a trench RIE machine with an in-situ monitoring system. For shrinkage of the chip size, a narrow trench formation process and a double trench (additional contact trench) structure are applied to the 3rd generation trench gate MOSFET. Using these new techniques, we succeeded in the development of a 3rd generation trench gate MOSFET with the lowest R_on value reported to date