2DEG-Concentration-Modulated High-Power-Density AlGaN/GaN RF HEMTs

Herein, by modulating 2DEG concentration (
${n} _{\mathbf {s}}$
), a superior GaN RF HEMT with a high-Al-content AlGaN barrier is reported for high power-density (
${P} _{\text {out}}$
) X-band applications. Thanks to a high
${n} _{\text {s}}$
of
${1}.{3}\times {10} ^{{13}}$
cm
$^{-{2}}$
enabled by the Al
$_{{0}.{32}}$
Ga
$_{{0}.{68}}$
N barrier, as well as the regrown n+ -GaN ohmic contacts, the device exhibits an output drain current (
${I} _{\text {D}}$
) of 1.6 A/mm, an on-resistance (
${R} _{\text {ON}}$
) of
$1.10\Omega ~\cdot $
mm, and maintain a breakdown electric field (
${E} _{\text {BC}}$
) of ~0.8 MV/cm. As a result, at 10 GHz,
${P} _{\text {out}}$
of 10.4 W/mm and power-added efficiency (PAE) of 63.2% are obtained at a moderate drain bias (
${V} _{\text {D}}$
) of 28 V. Notably, the results of
${I} _{\mathbf {D}}$
–
${E} _{\text {BC}}$
,
${P} _{\text {out}}$
–
${V} _{\text {D}}$
, and the figure-of-merit
${P} _{\text {out}}$
/
${V} _{D}$
of our device marks one of the best records among X-band GaN HEMTs, showing strong competitiveness of high-Al-content AlGaN/GaN HEMTs for high-
${P} _{\text {out}}$
RF applications.