Linearity Enhancement of AlGaN/GaN HEMTs With Selective-Area Charge Implantation

Abstract

In this letter, a linearity enhancement AlGaN/ GaN high electron mobility transistor (HEMT) with high power density and high efficiency has been achieved by selective-area charge implantation (SCI) for X-band application. Device-level transconductance compensation is realized by an under-gate SCI technique, which greatly improves the linearity of the device. The device presents a maximum drain current of 1390 mA/mm and a peak transconductance of 230 mS/mm. The gate voltage swing is up to 5.2 V, which is double of the conventional devices. At 12 GHz with a drain voltage of 25 V, the SCI device exhibits a peak power added efficiency of 47 % and a saturated output power density of 6.7 W/mm. In addition, the two-tone measurement results at 12 GHz show that the SCI device manifest an excellent linearity figure of merit OIP3/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{P}_{\text {DC}}$ </tex-math></inline-formula> of 11.2 dB, whereas that of the conventional HEMTs is only 5.5 dB. These results suggest SCI HEMTs have immense potential for microwave power amplifiers requiring high linearity.