This study demonstrates a novel enhancementmode tri-gate nanowire InAlN/GaN MOSHEMT with ultrasonic spray pyrolysis deposition (USPD) deposited Al2O3 as the gate dielectric layer. The proposed device reveals a threshold voltage (VTH) of +2.3 V and a maximum drain current (ID, max) of 705 mA/mm. It also exhibits superior electrical performances, including a high on-state/off-state current (Ion/Ioff) ratio of 109-1010, a steep subthreshold swing (SS) of 65 mV/decade, and a large breakdown voltage (BV) of 800 V with a leakage current of 0.7 μA/mm while keeping a low specific on-resistance (Ron, sp) of 1.04 mΩ·cm2. This novel E-mode device presents great potential for power device applications.

This brief reports, for the first time, an oxide passivated AlGaN/GaN high electron mobility transistor by using the hydrogen peroxide (H₂O₂) treatment. Characterizations by using electron spectroscopy for chemical analysis and transmission electron microscopy have been performed to verify the formation of surface oxide on the AlGaN barrier layer. The present design has demonstrated superior improvements of 41% in the maximum drain/source current density I_DS,max; 39% in the drain/source saturation current density at zero gate bias I_DSSO, 47% in the maximum extrinsic transconductance g_m,max, 53.2% in the two-terminal gate/drain breakdown voltage BV_GD 36% in the cutoff frequency f_T, and 20% in the maximum oscillation frequency f_max, as compared with an unpassivated conventional device.

This study demonstrates an amorphous indium-tin-zinc-oxide (a-ITZO) thin-film transistor (TFT) using an ultrasonic spray pyrolysis deposition (USPD) method. X-ray diffraction, X-ray photoelectron spectroscopy, Tauc plot, and photoluminescence spectrum are used to confirm the crystal structure, oxygen contents, energy bandgap, and the existence of oxygen deficiencies. Besides, these material characteristics are compared with a sputter-deposited ITZO film. The TFT based on the USPD-deposited ITZO shows better electrical performance than the TFT based on the sputter-deposited ITZO. In addition, the negative- /positive-bias illumination stress results indicate that the TFT based on the USPD-deposited ITZO film is more stable than the one based on the sputter-deposited ITZO.

Comparative studies for TiO ₂ -passivated Al _0.25 Ga _0.75 N/GaN heterostructure FETs (HFETs) and TiO ₂ -dielectric MOS-HFETs using nonvacuum ultrasonic spray pyrolysis deposition technique are made. Optimum device performances are obtained by tuning the layer thickness of TiO ₂ to 20 nm. High relative permittivity (k) of 53.6 and thin effective oxide thickness of 1.45 nm are also obtained. Pulse-IV, Hooge coefficient (α _H ), Transmission Electron Microscopy, and atomic force microscope have been performed to characterize the interface, atomic composition, and surface flatness of the TiO ₂ oxide. Superior improvements for the present TiO2dielectric MOS-HFET/TiO ₂ -passivated HFETs are obtained, including 47.6%/23.8% in two-terminal gate-drain breakdown voltage (BV _GD ), 111%/22.2% in two-terminal gate-drain turnON voltage (V _ON ), 47.9%/39.4% in ON-state breakdown (BV _DS ), 12.2%/10.2% in drain-source current density (I _DS ) at V _GS = 0 V (I _DSS0 ), 27.2%/11.7% in maximum I _DS (I _DS,max ), 3/1-order enhancement in ON/OFF current ratio (I _ON /I _OFF ), 58.8%/17.6% in gate-voltage swing linearity, 25.1%/13.2% in unity-gain cutoff frequency (f _T ), 40.6%/24.7% in maximum oscillation frequency (f _max ), and 33.8%/15.6% in power-added efficiency with respect to a Schottky-gated HFET fabricated on the identical epitaxial structure. The present MOS-HFET has also shown stable electrical performances when the ambient temperature is varied from 300 to 450 K.

This letter demonstrates an integration process of in situ Cl ^- doped Al ₂ O ₃ and gate recess technique to fabricate the enhancement mode AlGaN/GaN MOSHEMTs. The Cl ^- doped Al ₂ O ₃ thin film is deposited by the ultrasonic spray pyrolysis deposition and characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The relative permittivity of Cl ^- doped Al ₂ O ₃ is higher than the pure Al ₂ O ₃ and the output current is enhanced. The threshold voltage of the enhancement mode AlGaN/GaN MOSHEMT with the Cl ^- doped Al ₂ O ₃ gate dielectric layer rose from 0.2 to 1.3 V. Furthermore, the breakdown voltage of present enhancement mode AlGaN/GaN MOSHEMT reached 650 V. It was also found that the MOSHEMT with Cl ^- doped Al ₂ O ₃ has higher gate leakage than that with pure Al ₂ O ₃ . The thermal stability of threshold voltage and current collapse phenomenon is described in this letter.