Ultra-low on-resistance trench gate MOSFET with buried p-island

A high voltage trench gate MOSFET (TMOS) with an ultra-low specific on-resistance (R on ) is proposed. The MOSFET is characterized by the combination of a trench gate and two buried p-islands (BPIs) formed in the n-epitaxial layer by the self-alignment (BPIs TMOS). In the blocking state, the superjunction structure, formed by the BPIs/n-drift region, sustains a higher breakdown voltage (BV). The high drift region doping concentration due to the superjunction structure lowers R on . Influences of structure parameters on the breakdown voltage and specific on-resistance are analyzed for the proposed device by simulator MEDICI. BV of 85V and R on of 22mΩ.mm 2 are obtained.