In this work, we successfully demonstrated In_0.53Ga_0.47As/InAs/In_0.53Ga_0.47As composite channel metamorphic high electron mobility transistors (mHEMTs) on a GaAs substrate. The fabricated mHEMTs with a 100 nm gate length exhibited excellent DC and logic characteristics such as V_T = −0.13 V, g_m,max = 949 mS/mm, subthreshold swing (SS) = 84 mV/dec, drain-induced barrier lowering (DIBL) = 89 mV/V, and I_on/I_off ratio = 9.8 × 10³ at a drain-source voltage (V_DS) = 0.5 V. In addition, the device exhibited excellent high-frequency characteristics, such as f_T/f_max = 261/304 GHz for the measured result and well-matched modeled f_T/f_max = 258/309 GHz at V_DS = 0.5 V, which is less power consumption compared to other material systems. These high-frequency characteristics are a well-balanced demonstration of f_T and f_max in the mHEMT structure on a GaAs substrate.

Our investigation focused on assessing the influence of the metamorphic buffer in metamorphic high-electron-mobility transistors (MHEMT) that were grown on GaAs substrates. While an MHEMT exhibited elevated off-state current levels, its direct current (DC) and radio frequency (RF) traits were found to be comparable to those of InP-based lattice-matched high-electron-mobility transistors (LM-HEMTs). However, the Pulsed I–V measurement results confirmed the presence of the fast transient charging effect, leading to a more substantial degradation in drain current observed in MHEMT. In addition, through the low-frequency noise characteristics, it was confirmed that the dominant trapping location was located in the bulk site. The slope of the 1/f noise measurement indicated that the primary trapping site was in proximity to the bulk traps. The carrier-number-fluctuation (CNF) model was employed to extract the bulk trap density (N_t). For the LM-HEMTs, the value was at 3.27 × 10¹⁶ eV⁻¹·cm⁻³, while for the MHEMT, it was 3.56 × 10¹⁷ eV⁻¹·cm⁻³.