A Novel Resurf Stepped Oxide MOSFET with Slope Field Plate

In this work, a new charge-coupling structure of RSO MOSFET with slope field plate is proposed. The design method is developed by theoretical analysis. In addition, a fabrication method using multi-plate to fit slope method is introduced. Then, a 250V structure was simulated to verify the theoretical analysis by TCAD. It is demonstrated that the structure overcomes the non-uniformity of electric field in drift region in traditional RSO MOSFET. The trade-off between the Ron and BV— “silicon limit” has been broken, for the Rdson=116 mΩ/mm2 in this structure.