Enhancement-Mode P-Channel GaN/InAlN T-Shaped FinFETs with ION> 60 mA/mm and Adjustable VTH of −0.7 V – −3.1 V

In this letter, we present high-performance enhancement-mode (E-mode) p-channel T-shaped Fin Field-Effect Transistors (FinFETs) fabricated on a proposed p-GaN/ AlN/InAlN epitaxial structure. A T-shaped Fin with a smooth and steep sidewall was achieved by utilizing electron-beam lithography and anisotropic sidewall wet etching in tetramethyl ammonium hydroxide (TMAH) solution. A low ohmic contact resistance
$(R_{\mathrm{C}})$
of 11.6
$\Omega .mm$
was attained by using Ti mask process. Moreover, the devices exhibited a high on-current density (I
ON
) of 61.5 mA/mm and a high ON-OFF current ratio
$(I_{\text{ON}}/I_{\text{OFF}})$
of 5 ×10
⁶
. An adjustable threshold voltage (V
TH
) of −0.7 V – −3.1 V was achieved by controlling the width of the Fin, which can be preferably used to match n-channel GaN devices for GaN CMOS design. Compared with the reported p-channel GaN FETs on HEMT platforms, especially the E-mode FETs, the fabricated devices show more excellent performance in terms of ION,
$V_{\text{TH}}$
, and
$R_{\text{ON}}$
. These results unveil the excellent prospects of the fabricated devices for future monolithic integration of GaN-based logic and power applications.