The Mechanism of Field-Plate Induced the Breakdown Voltage Change of High Voltage LDMOS

The field-plate (FP) has been commonly used to increase the breakdown voltage for achieving the low on-resistance (Ron) high-voltage (HV) device. However, the mechanism of the FP induced the breakdown-voltage change of HV device is not fully understood. From the TCAD simulation, it finds that the electrical field of the reduced-surface field (RESURF) region of HV device is affected by the thickness differences of the dielectrics above this region. As the field-plate is inserted into these dielectrics, the dielectric thickness differences are reduced to lead to the electrical field suppression of RESURF region, resulting in the breakdown voltage increase of HV device.