Substrate-bias effect on the breakdown characteristic in a new silicon high-voltage device structure

A novel silicon double-RESURF LDMOS structure with an improved breakdown characteristic by substrate bias technology(SB) is reported.The P-type epitaxial layer is embedded between an N-type drift region and an N-type substrate to block the conduction path in the off-state and change the distributions of the bulk electric field.The substrate bias strengthens the charge share effect of the drift region near the source,and the vertical electric field peak under the drain is decreased,which is especially helpful in improving the vertical breakdown voltage in a lateral power device with a thin drift region.The numerical results by MEDICI indicate that the breakdown voltage of the proposed device is increased by 97%compared with a conventional LDMOS,while maintaining a low on-resistance.