A New Solution for Superjunction Lateral Double Diffused MOSFET by Using Deep Drain Diffusion and Field Plates

A new solution based on the concept of a deep drain diffusion combined with field plates (FPs) is proposed for the superjunction lateral double diffused MOSFET (SJ-LDMOS) device. The deep drain diffusion suppresses the curvature effect of the conventional SJ-LDMOS and the FPs optimize the electric field distribution further. Simulated results show that the proposed SJ-LDMOS exhibits figure of merits of 12.8 and 8.5 MW/cm² for 700 and 1200 V ratings, respectively, which are about 20% better than the prior art. Moreover, the proposed SJ-LDMOS is less sensitive to the charge imbalance. Using the isotropic etch technique followed by implantation, the deep drain diffusion is easy to be fabricated.