Novel GaAs Switch for Compact and Efficient Power Conversion

The development and demonstration of a novel GaAs switch called Substrate-Driven FET (SDFET) is reported in this paper. The SD-FET process is compatible with standard large volume pHEMT processes and the device has far superior switching properties compared to state-of-the-art Si devices. This combination of cost effectiveness and excellent performance makes the SD-FET vital for meeting the challenging power requirements of next generation portable applications. Devices with current capability of 20A with a gate width of 1 meter, specific onresistance of 0.26m Ω-cm 2 , and turn-on and turnoff transitions less than 1nsec have been demonstrated. Power losses due to conduction, gate charge, output capacitance and switching transitions are lower than that of commercially available state-of-the-art Si devices, thereby validating the capability of the SD-FET in enabling compact and highly efficient power conversion. The performance of the SD-FET in a multiphase buck converter application was analyzed showing at least 9 percentage points improvement in efficiency over an equivalently rated Si-based counterpart.