This work presents the fabrication and performance analysis of a novel enhancement-mode (E-mode) vertical β-Ga₂O₃ (010) U-trench MOSFET featuring an in-situ Mg-doped current blocking layer (CBL) for high-power applications. Utilizing metal-organic chemical vapor deposition (MOCVD), we achieved precise Mg doping of 1.3×10¹⁹ cm⁻³ within the CBL to enhance current blocking capability while maintaining a robust threshold voltage of 5 V and a low on-state resistance of 5 mΩ .cm². The device achieved an on-current of 1.56 kA/cm² at V_GS = 20 V and V_DS = 40 V. The fabricated devices demonstrate a peak breakdown voltage of 101 V with an average breakdown field strength of up to 1.68 MV.cm⁻¹. The calculated power device Figure of Merit is 2 MW.cm⁻².

Herein, we present a detailed analysis of the effects of O2 plasma treatment on the AlGaN barrier volume trap states in an Al0.45Ga0.45N/GaN high-electron mobility transistor. Compared to that of the as-grown sample, the single short-pulse ${I}_{D}$ – ${V}_{\text {GS}}$ characterization of the plasma-treated sample exhibited lower charge trapping inside the AlGaN barrier. The 1/ ${f}$ low-frequency noise characterization revealed a significant reduction of approximately 67% in the volume trap density of the AlGaN barrier layer after O2 plasma treatment. This was achieved by the formation of Al–O and Ga–O bonds via the penetration of oxygen ions into the AlGaN bulk, which resulted in reduced trap state density in the AlGaN barrier. In addition, the Schottky characteristics were improved notably. Consequently, the O2 plasma-treated sample did not display current collapse and showed steady drain current output under the reverse-sweep drain-stress bias conditions. Furthermore, the plasma treatment significantly reduced the RF transconductance ( ${g}_{m}$ ) collapse in the as-grown sample, and significantly increased the ${f}_{T}/{f}_{\text {max}}$ of the plasma-treated sample from 65/70 to 120/230 GHz for ${L}_{g}$ = 80 nm devices, respectively. Last, the O2 plasma-treated sample showed substantial improvements in ${P}_{\text {out}\_\max}$ , power added efficiency (PAE), and linear gain from 1.25 W/mm, 20%, and 15 dB to 2.4 W/mm, 50%, and 19 dB, respectively.

We presented an explicit empirical model of the thermal resistance of AlGaN/GaN high-electron-mobility transistors on three distinct substrates, including sapphire, SiC, and Si. This model considered both a linear and non-linear thermal resistance model of AlGaN/GaN HEMT, the thickness of the host substrate layers, and the gate length and width. The non-linear nature of channel temperature—visible at the high-power dissipation stage—along with linear dependency, was constructed within a single equation. Comparisons with the channel temperature measurement procedure (DC) and charge-control-based device modeling were performed to verify the model’s validity, and the results were in favorable agreement with the observed model data, with only a 1.5% error rate compared to the measurement data. An agile expression for the channel temperature is also important for designing power devices and monolithic microwave integrated circuits. The suggested approach provides several techniques for investigation that could otherwise be impractical or unattainable when utilizing time-consuming numerical simulations.

We investigated the effects of quantum confinement in determining the interface traps (Dit) and border traps (Nbt) of ALD deposited Al2O3 with temperature variations onto InxGa1-xAs on a 300-mm Si (001) substrate. We also analysed the impact of these effects on the total gate capacitance of high-k/Si and high-k/InxGa1-xAs structures using 1D Poisson-Schrodinger solver simulation tool (Nextnano). While quantum confinement has no or very little impact on the gate capacitance of high-k/Si structure, it has a considerably high amount of impact on the high-k/InxGa1-xAs structures and substantially lowers the total gate capacitance. To reflect the actual thickness between the insulator-semiconductor interface and charge centroid, capacitance-equivalent-thickness was used to reflect the effects of quantum confinement in the InxGa1-xAs layer. The Dit and Nbt values extracted using capacitance-equivalent-thickness were observed to be around 10% and 25%, respectively, higher than the values of extraction with equivalent-oxide-thickness.

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.