New Superjunction LDMOS With $N$ -Type Charges\´ Compensation Layer

A new superjunction lateral double diffused MOSFET (LDMOST) is designed with an N-type buried layer in the P-substrate near the drain to suppress the effect of substrate-assisted depletion resulting from N-type charges´ compensating charges´ imbalance between the pillars of the superjunction layer. By the effect of the electric field modulation, a more uniform surface electric field is obtained by the new high electric field peak introduced by the p-n junction of the P -substrate and N-type charges´ compensation layer. The new effect of reduced bulk field is introduced to improve the vertical breakdown voltage (BV) by reducing the high bulk electric field around the drain. Fabricated N-buried SJ LDMOST with a drift region length of 35 mum and a pillar width of 4.0 mum exhibits a specific on resistance of 98 mOmegamiddotcm² and a BV of 410 V.