New-superjunction LDMOST with N-buffer layer

A buffered superjunction LDMOST (SJ-LDMOST) structure, which reduces substrate-assisted depletion effects, is proposed and the experimental implementation in a CMOS technology are presented. The proposed structure uses an N-buffer layer between the pillars and the P-substrate to achieve charge compensation between the pillars, the N-buffer layer, and the P-substrate. The practical implementation involves the additional formation of the N-buffer and the pillars in a 0.8-mu m CMOS process. Both of the simulation and the experimental results confirm that the substrate effects are suppressed by the buffered structure.