Substrate Current Improvement and Investigation in Low Voltage Power Ldmos with A Novel Design

A lateral double-diffused metal–oxide–semiconductor (LDMOS) field-effect transistor with stepped filed plates (SFP) was investigated in this work. The second substrate current peak was highly suppressed by a novel structure design. The novel SFP-NLDMOS device features an additonal CFP at the dain side. This improvement was verified in our 24V NLDMOS and can be applied to other low-voltage power LDMOS with different FP design if neccessary. It was revealed that the second substrate current peak of 24V NLDMOS was decreased by over 60% within our new design. The electric field at drainside was significantly rudced. Therefore, the kirk effect was hgihly suppressed at both high gate and drain voltage. These results were verified by TCAD simulation.