InAlN/GaN MOSHEMT With Self-Aligned Thermally Generated Oxide Recess

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> We report on lattice-matched InAlN/GaN MOSHEMTs with an oxide-filled recess, self-aligned to the gate prepared by thermal oxidation at 800 <formula formulatype="inline"><tex Notation="TeX">$^{\circ}\hbox{C}$</tex></formula> in oxygen atmosphere. The device delivered a maximum current density of 2.4 A/mm. Pulse measurements showed no apparent lag effects, indicating a high-quality native oxide. This was confirmed by monitoring the radio-frequency load lines in the time domain. The MOSHEMT yielded a power density of 6 W/mm at a drain voltage as low as 20 V and at 4 GHz, a power added efficiency of 32% and an <formula formulatype="inline"><tex Notation="TeX">$f_{t}$</tex></formula> and <formula formulatype="inline"><tex Notation="TeX">$f_{\max}$</tex></formula> of 61 and 112 GHz, respectively, illustrating the capability of such MOSHEMT to operate at high frequencies. </para>