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

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 ( ${f}_{\text {T}}$ ) linearity. It is found that the Gm profile for Fin-like HEMTs can be optimized by choosing appropriate device parameters, including the etching depth ( ${H}_{\text {R}}$ ) and width ( ${W}_{\text {R}}$ ) of recess region, as well as the duty ratio ( $\alpha $ ) of the planar elements in a periodic unit along the gate width. In general, not only does ${W}_{\text {R}}$ affect the gate voltage swing (GVS) but also ${H}_{\text {R}}$ and $\alpha $ 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 ${f}_{\text {T}}/{f}_{\text {max}}$ 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.