Abstract: A new super junction LDMOST structure that suppresses the substrate-assisted depletion effect is designed with an n+-floating layer embedded in the high-resistance p-type substrate by implanting phosphor or arsenic.This effect results from a charge imbalance between the n-type and p-type pillars when the n-type pillars are depleted by p-type substrate.The high electric field around the drain is reduced by the n+-floating layer due to the REBULF effect,which causes the redistribution of the bulk electric field in the drift region,and thus the substrate supports more biases.The new structure features high breakdown voltage,low on-resistance,and charge balance in the drift region.

Key words: super junction, LDMOST, substrate-assisted depletion, n+-floating layer, breakdown voltage