High voltage SOI SJ-LDMOS with dynamic buffer

A new buffered super junction (SJ) LDMOS on silicon-on-insulator (SOI) is proposed to eliminate the substrate-assisted depletion effect. The trenched buried oxide is self-adaptive to collect the additional charges according to the variable electric field strength, which forms a dynamic buffer between the SJ and the substrate. The collected charges compensate the N pillars, resulting in the charge balance between N and P pillars of the S J. Numerical simulation results indicate that the proposed device features high breakdown voltage and low on-resistance.