P-Regions With U Shape Beneath N-Drift Region In LDMOS Transistor (UND-LDMOS) A Novel Technique For Electric Field Control To Improve Breakdown Voltage

High breakdown voltage and reduced on-resistance are desired characteristics in power MOSFETs. In orderto obtain an excellent performance of lateral double-diffused MOSFET (LDMOS) devices, a novel structureof LDMOS transistor is proposed in this paper. In U shape N-drift region LDMOS (UND-LDMOS), Pregionsare considered in the N-drift region. The balanced charges between P-regions and N-drift helpsextending the depletion regions that causes uniform electric field. So, the breakdown voltage increases inthis new structure in comparison to the conventional LDMOS structure (C-LDMOS). Also, the simulationwith ATLAS simulator shows that selecting the optimum values of p-region length and doping density,causes the decreased specific on-resistence. Therefore, high performance of UND-LDMOS extendsLDMOS application between other power devices. Moreover, the simulation shows the p-regions under thedrift region helps to reduce the drift region length without further decreasing the conduction area. So,specific on-resistance of UND-LDMOS is reduced in comparison to the convensional LDMOS structure(C-LDMOS).

Keywords:

LDMOS , Breakdown voltage , Specific on-resistance , Drift region