Dynamic Characteristics of Novel Super-Junction LDMOS Switches under Charge Imbalance Conditions

The inductive switching performance of a smart super-junction (SJ) LDMOS switch is simulated and analysed, together with the reverse recovery properties of its internal diode. The SJ power switch under investigation differs from the conventional one in the so-called SJ structure which, in this case, consists of an array of p-type round pillars embedded in the n-type drift region. In view of the tolerances achievable in the present fabrication technology, the effect of slightly unbalanced doping charges in the SJ structure is of utmost importance and, hence, studied in detail. Two different SJ structures have been designed to tackle the effect of substrate-aided depletion on the blocking capability of the SJ switch. The 3D-simulation results reveal that a proper design of the SJ structure not only suppresses the substrate effect, but also enhances the switching capability of the SJ switch