Influence of Fin-Like Configuration Parameters on the Linearity of AlGaN/GaN HEMTs

Abstract

In this letter, we explore the impact of configuration parameters for Fin-like high-electron-mobility transistors (HEMTs) formed by partially etching barrier under the gate on improving transconductance (Gm) and cutoff frequency ( f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) linearity. It is found that the Gm profile for Fin-like HEMTs can be optimized by choosing appropriate device parameters, including the etching depth ( H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</sub> ) and width ( W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</sub> ) of recess region, as well as the duty ratio ( α) of the planar elements in a periodic unit along the gate width. In general, not only does W <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</sub> affect the gate voltage swing (GVS) but also H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</sub> and α have an important role in Gm profile flatness. In addition, the fabricated Fin-like HEMTs shows a GVS of the transconductance plateau larger than 5.6 V and a constant f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> /f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> of 45 GHz/65 GHz over a wide gate voltage range. Furthermore, the proposed architecture also features an exceptional linearity performance at 8 GHz with an output third-order intercept point (OIP3) of 38.5 dBm, whereas that of the planar HEMT is 31 dBm. The device demonstrated in this article has great potential to be a new paradigm for future wireless communication systems where high linearity is essential.