25 amp, 500 volt insulated gate transistors

The concept of merging MOS gating with bi-polar current conduction to create a new family of power semiconductor devices with superior electrical characteristics was reported at last year´s conference (1). This paper will report the development of an improved device structure which enables increasing the operating current density even further so that the insulated gate transistors (IGT´s) can be operated at current densities of over 200 Amperes per cm², i.e., at over 20 times that of the power MOSFET. As discussed in Reference (1), the maximum operating current density is limited by the latch-up of a parasitic thyristor inherent in the device structure. Using two dimensional computer modelling, it has been shown that this latch-up can be suppressed by reducing the lateral sheet resistance of the p-base. This has been experimentally achieved by the addition of a high concentration boron diffusion in the DMOS cells. The electrical characteristics of 25 Amp, 500 Volt IGT devices designed and fabricated using the modelling results will be presented. These devices have the highest power handling capability (12.5 kVA) achieved in power MOS devices to date.