A Higher Breakdown Voltage and Lower Specific on Resistance Superjunction MOSFET with Non-normal Breakdown Voltage Distribution

摘要

Trench filling epitaxy growth is a widely adopted method for fabricating superjunction MOSFET. Tilted trench is used to reduce the crystal defect during the epitaxy filling which disturbs the charge balance between P Pillar and N type drift region leading to lower breakdown voltage. By utilizing double epilayer strucutre instead of the previously used uniformly doped epitaxy layer (single epilayer) on a heavily doped silicon substrate, a higher breakdown voltage and lower specific on resistance is obtained. Monte carlo method is implemented to investigate its breakdown voltage distribution. A non-normal breakdown voltage distribution is verified by samples fabricated using this method.