Study on the Intrinsic Origin of Output Capacitor Hysteresis in Advanced Superjunction MOSFETs

The output capacitor COSS of the superjunction (SJ) MOSFET extracted from large-signal measurements has recently been found to have hysteresis characteristic. This letter reveals the intrinsic origin of COSS hysteresis in advanced SJ MOSFETs with the help of numerical simulations. The results show that the extracted hysteresis area of COSS is influenced by dVDS/dt and changes with the excitation voltage wave. Different transient COSS extracted at the same VDS during the charge process and the discharge process are shown to be rated to different depletion boundary widths, and the root cause is the finite velocities of carriers in semiconductor.