A low specific on-resistance power trench MOSFET with a buried-interface-drain

• A novel trench power MOSFET with a buried-interface-drain (BID MOSFET) is proposed.
• The influences of structure parameters on the device performances are investigated.
• An ultralow Ron,sp of 0.85mΩ cm2 is obtained with a breakdown voltage (VB) of 133 V.
• BID MOSFET is compared with several previous-proposed trench MOSFETs.
• A significantly optimized dependence of Ron,sp on VB is obtained.

A novel trench power MOSFET with a buried-interface-drain (BID MOSFET) is proposed in this paper. The drain n+ region of BID MOSFET extends to the surface of p− substrate and is buried along the interface of the substrate–layer and epitaxy-layer, which shortens the motion-path in the high-resistance n− drift region for the carriers, and therefore, exhibits a lower specific on-resistance (Ron,sp) and a higher figure-of-merit. The influences of structure parameters on the device performances are investigated. An ultralow Ron,sp of 0.85 mΩ cm2 is obtained with a breakdown voltage (VB) of 133 V. BID MOSFET is compared with several previous-proposed trench MOSFETs, and a significantly optimized dependence of Ron,sp on VB is obtained.