Comparison of Si, GaAs, SiC and GaN FET-type switches for pulsed power applications

Among the present limitations on the peak voltage of traditional Si-MOSFET switches are fundamental materials properties that are related both to intrinsic properties (such as bandgap), and to defects. Switches fabricated from semiconductors such as GaAs, SiC and GaN hold promise if hold-off voltages of several kilovolts and fast rise rates are needed. High power and short pulse (< 1 μs) applications require both fast switching speed and great current handling capability. The question arises whether any single material has all of these desired properties or whether there are intrinsic limitations. In order to investigate this, we have performed simulations of the electrical properties of FET-type switches fabricated from each of these materials. Both perfect material properties and the effects of defects have been included. The simulation results show that deep level defects degrade the device performance. Based on our simulations and on the available data, in the near term, 4H-SiC is the most attractive of the four materials for pulsed power applications.