Electron velocity of 6 × 107 cm/s at 300 K in stress engineered InAlN/GaN nano-channel high-electron-mobility transistors

Abstract

A stress engineered three dimensional (3D) Triple T-gate (TT-gate) on lattice matched In 0.17 Al 0.83 N/GaN nano-channel (NC) Fin-High-Electron-Mobility Transistor (Fin-HEMT) with significantly enhanced device performance was achieved that is promising for high-speed device applications. The Fin-HEMT with 200-nm effective fin-width (W eff ) exhibited a very high I Dmax of 3940 mA/mm and a highest g m of 1417 mS/mm. This dramatic increase of I D and g m in the 3D TTgate In 0.17 Al 0.83 N/GaN NC Fin-HEMT translated to an extracted highest electron velocity (v e ) of 6.0 Â 10 7 cm/s, which is $1.89Â higher than that of the conventional In 0.17 Al 0.83 N/GaN HEMT (3.17 Â 10 7 cm/s). The v e in the conventional III-nitride transistors are typically limited by highly efficient optical-phonon emission. However, the unusually high v e at 300 K in the 3D TT-gate In 0.17 Al 0.83 N/GaN NC Fin-HEMT is attributed to the increase of in-plane tensile stress component by SiN passivation in the formed NC which is also verified by micro-photoluminescence (0.47 6 0.02 GPa) and micro-Raman spectroscopy (0.39 6 0.12 GPa) measurements. The ability to reach the v e ¼ 6 Â 10 7 cm/s at 300 K by a stress engineered 3D TT-gate lattice-matched In 0.17 Al 0.83 N/GaN NC Fin-HEMTs shows they are promising for next-generation ultra-scaled highspeed device applications. V

High-Current Submicrometer Tri-Gate GaN High-Electron Mobility Transistors With Binary and Quaternary Barriers

“…In contrast to the medium-level saturation current densities of 1.5 A/mm achieved by the planar FETs, nano-channel FinFETs have delivered very high maximum current densities up to 3.8 A/mm. When compared to the state-of-art, this is one of the highest values recorded by GaN-based Tri-gate HEMTs following the reported devices by Arulkumaran et al [16]. It also needs to be noted that the use of sidewall Si 3 N 4 layer during the processing of AlN/GaN FinFETs has enabled eliminating higher gateleakage currents at very high applied gate bias voltages as it introduces metal-insulator-semiconductor (MIS) interfaces only at the sidewalls of the fin structures.…”

“…In this letter, we adopt the lattice-matched InAlGaN and AlN-barrier layers [5]- [8] to improve the saturation drain current density and transconductance of Tri-gate [9]- [16] HEMTs, compared to the AlGaN. It has already been determined in an earlier study [5] that the use of quaternary layers bear great potential to enhance the performance of GaN HEMTs, having reached carrier mobilities over 1600 cm 2 /Vs.…”

Impact of Al₂O₃ Passivation on AlGaN/GaN Nanoribbon High-Electron-Mobility Transistors

“…While previous reports have indicated that mechanical stress may influence electron velocity in nanoribbons [25], in this paper, only the influence of passivation on scattering rate has been evaluated. The mean free path (mfp) is a quantity directly related to the scattering time.…”

Nano-channel InAlN/GaN Fin-HEMTs for ultra-high-speed electronics

“…The layer structure and a complete device process details can be found in Ref [5,6]. The height of the fin (H Fin ) is 12 nm.…”

“…By scaling down the fin widths (20-30 nm) and gate length (L g =70-80 nm), InAlN/GaN I-gate FinFETs on SiC exhibited I Dmax =3500 mA/mm and g mmax =800 mS/mm. More recently, we have demonstrated InAlN/GaN NC Tgate Fin-HEMTs on Si with impressive device performances [5,6]. In this paper, we report the device performance of InAlN/GaN NC Fin-HEMTs with T-gate measured at V D of 0.5 and 6 V. In addition, the measured parameters were also compared with a conventional InAlN/GaN HEMTs on a Si substrate.…”