A low on-resistance, high-current GaAs power VFET

Abstract

We have developed a new fabrication process for GaAs VFETs that results in excellent performance in a 10 A prototype designed for switching in low voltage synchronous rectifier applications. The new fabrication process uses a buried carbon-doped GaAs gate structure for the gate electrodes and an epitaxial overgrowth step. We have demonstrated 10 A devices with 3.5 cm of gate width and 1.5 mohm of on-resistance (specific on-resistance of 84 μohm-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ). The device required a 0.5 μm channel etched between 0.5 μm gates placing stringent requirements on the gate side wall etch profile and epitaxial doping uniformity.