Improved microwave and noise performance of InAlAs/InGaAs metamorphic high-electron-mobility transistor with a liquid phase oxidized InGaAs gate without gate recess

The metal-oxide-semiconductor metamorphic high-electron-mobility transistor (MOS-MHEMT) with an oxide grown by liquid phase oxidation on the InGaAs capping layer without a gate recess exhibits a lower leakage current density with suppressed impact ionization, better microwave characteristics, and improved high frequency noise performance compared to the conventional MHEMT with a recessed gate. The improved high frequency performance is due to the lower gate-source and gate-drain capacitances of the InAlAs/InGaAs MOS-MHEMT. Reduced surface recombination and impact ionization may also contribute to the improved frequency response, noise performance, and associated gain.