Characteristics and utilization of a new class of low on-resistance MOS-gated power device

Abstract

A new class of MOS-gated power semiconductor devices Cool MOS/sup TM/ has been introduced with a supreme conducting characteristic that overcomes the high on-state resistance limitations of high voltage power MOSFETs. From the application point of view, an immediate and very frequently asked question arises: does this device behave like a MOSFET or an insulated gate bipolar transistor (IGBT)? The goal of this paper is to compare and contrast the major similarities and differences between this device and the traditional MOSFET and IGBT. In this study, the new device is fully characterized for its (1) conduction characteristics, (2) switching voltage, current, and energy characteristics, (3) gate drive resistance effects, (4) output capacitance, and (5) reverse bias safe operating areas. Experimental results indicate that the conduction characteristics of the new device are similar to the MOSFET but with much smaller on-resistance for the same chip and package size. The switching characteristics of the Cool MOS are also similar to the MOSFET in that they have fast switching speeds and do not have a current tail at turn-off. However, the effect of the gate drive resistance on the turn-off voltage rate-of-rise (dv/dt) is more like an IGBT. In other words, a very large gate drive resistance is required to have a significant change on dv/dt, resulting in a large turn-off delay. Overall, the device was found to behave more like a power MOSFET than like an IGBT.