Nozomu Akagi

600 V-class trench-filling super junction power MOSFETs for low loss and low leakage current

Trench-filling technology realizes an outstanding productivity for fabricating the Super Junction (SJ) structure of SJ-MOSFETs. However, crystal defects that occur during epitaxial growth are causing poor electrical characteristics. Our optimized process reduced the number of crystal defects from over 2000/mm2 to under 10/mm2. As a result, we have achieved both low loss and low leakage current and high ruggedness for the first time with the SJ-MOSFET fabricated by the trench filling epitaxial growth technique. The drain leakage current decreased from tens of micro amperes to tens of nano amperes. The improved SJ-MOSFET has achieved an avalanche current of 35 A, a specific on-resistance (RonA) of 13.5 mΩcm2, an output capacitance stored energy (Eoss) of 10.3 μJ, and a diode commutation speed (di/dt) of over 2000 A/μs, respectively.