Current Breakdown Voltage Research Articles

Gate reliability enhancement of p-GaN gate HEMTs with oxygen compensation technique

Improved p-GaN gate reliability is achieved through a simple oxygen compensation technique (OCT), which involves oxygen plasma treatment after gate opening and subsequential wet etching. The OCT compensates for the Mg acceptors near the p-GaN surface, leading to an extended depletion region under the same gate bias and thus reducing the electric field. Furthermore, the Schottky barrier height also increases by OCT. Consequently, suppressed gate leakage current and enlarged gate breakdown voltage are achieved. Notably, the maximum applicable gate bias also increases from 4 V to 8.1 V for a 10 year lifetime at a failure rate of 1%.

Regulation the graphene oxide concentration for the low energy consumption ceramic coating

In order to meet the demand of sustainable energy development in today's world, it is imperative to implement low energy processing technologies, such as low energy surface treatment. In this study, a low energy consumption plasma electrolytic oxidation (PEO) surface treatment technology with low breakdown voltage and high coating efficiency is designed by adding graphene oxide (GO). It is found that the addition of GO provided more possibilities for the formation of interionic reactions of passivation films, which results in the passivation current density and breakdown voltage reducing by 60 % and 22.31 %, respectively. Furthermore, GO induces a shift in the discharge form from metal/oxide interface discharge to oxide/electrolyte interface discharge, which enhances the growth efficiency of the ceramic coating by 24.70 %, and decreases the energy consumption of each reaction stage by 9.00 %, 10.45 % and 10.84 %. The obtained low energy consumption coating, with low overall porosity (3.38 vol%), exhibits a smooth surface and eliminates channels for corrosive ions, which improves the anti-friction property and corrosion resistance.

Thermal Aging Characteristics of Silicone Rubber Exposed to Mineral Oil

Room temperature vulcanized (RTV) silicone rubber is extensively utilized as a coating material for power transformer bushings because of its high hydrophobicity and excellent anti-pollution flashover resistance. However, the performance of silicone rubber may suffer significantly when exposed to mineral oil. Till now, literature available on understanding the degradation behavior of silicone rubber exposed to mineral oil at different temperatures is very rare. Therefore, in the present work oil immersion test is performed. RTV silicone rubber was thermally aged in mineral oil at 40°C and 80°C for 200 hours. Post ageing, to examine the changes in the surface properties of the aged specimens 3D microscopy, scanning electron microscopy (SEM) analysis, contact angle, proof tracking index (PTI), and shore hardness measurements were made. The results indicate that the degree of surface degradation was proportional to the temperature. Further, thermogravimetric analysis (TGA), differential thermal analysis (DTA), and infrared thermography were employed to evaluate the thermal properties of aged and unaged specimens. TGA-DTA and infrared thermography indicated a remarkable reduction in thermal stability and heat dissipation capability post mineral oil ageing. The effect became more adverse with increasing ageing temperature. Also, ageing resulted in a decrease in alternating current (AC) breakdown voltage and PTI. Finally, all the experimental outcomes were correlated and the degradation dynamics of mineral oil-aged silicone rubber are explained in detail through possible chemical reactions, fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDAX) investigations.

Numerical Calculation of Direct Current Breakdown Voltage for Complex Short Air Gaps under Varying Altitudes

With the increasing construction of ultra-high voltage direct current transmission in high-altitude environments, it becomes crucial to explore the impact of altitude on the short-gap discharge characteristics. To this end, this study proposes a finite element simulation and calculation method for the direct current (DC) breakdown voltage of actual complex short-gap structure under varying altitudes based on the Townsend criterion and the streamer criterion. The method is verified by combining the discharge experiments in Beijing, Qinghai, and Tibet. The results demonstrate that this method can effectively calculate the DC breakdown voltage of gaps between damping capacitors with a relative error range of -3.64% to 0.2%. The research results provide new insights for insulation evaluation of short-gap structures under varying altitudes.

An Experimental Study on Novel Gas Discharge Tubes With Graphene as Electron Emission Material

Electrical equipment is subjected to gas discharge tube (GDT) direct current (dc) breakdown voltage dispersion and breakdown voltage drop after a surge. It is noteworthy that GDT damage may even cause the failure of electrical equipment. Accordingly, the chemical vapor deposition (CVD) of graphene was proposed in this study as an electron emission material of the GDT based on the existing electron powder GDT. The GDT exhibiting a voltage class of 470 V was prepared, and its structure and surge characteristics were analyzed. The effects of gas pressure, aging time, and ambient temperature on the breakdown voltage of the graphene GDT were studied. The surge process of the graphene GDT was simulated using the 8/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$20~\mu \text{s}$ </tex-math></inline-formula> impulse current generator, and the resistance ability of the graphene GDT against the surge was examined. Moreover, it was compared with the same type of commercial electron powder GDT. As indicated by the experimental results, a positive correlation was identified between the gas pressure and the dc breakdown voltage of the graphene GDT under a certain pressure. The effect of aging time and ambient temperature on dc breakdown voltage was limited. The breakdown voltage of the graphene GDT was first increased and then decreased with the increase in the number of surges. After 100 surges, the breakdown voltage of the graphene GDT stabilized at 350 V, whose stability was better than that of the electron powder GDT. The above-described analysis confirmed that graphene GDT exhibits better surge resistance ability.

Influence of the electrolyte conductivity on the critical current density and the breakdown voltage

The work investigates influence of the electrolyte conductivity on the onset of partial contact glow discharge electrolysis (CGDE) in a water electrolysis. Critical current density (CCD) and breakdown voltage were measured together with in situ observation of hydrogen bubble behavior, whose influence has not been focused on. For a fixed current during normal electrolysis, hydrogen coalescence adjacent to cathode surface was invigorated at a lower conductivity. Photographic analyses elucidated the hydrogen coalescence characteristics by quantifying size and population of detached hydrogen bubbles. The CCD increased about 104% within given range of conductivity (11.50–127.48 mS·cm–1) due to impaired bubble coalescence, which delays hydrogen film formation on the cathode. Meanwhile, decreasing trend of breakdown voltage was measured with increased conductivity showing maximum drop of 74%. It is concluded that onset of partial CGDE is directly affected by hydrodynamic bubble behaviors, whereas the electrolyte conductivity affects the bubble formation characteristics adjacent to cathode electrode.

Low leakage current and high breakdown voltage of AlGaN/GaN Schottky barrier diodes with wet-etching groove anode

AlGaN/GaN heterojunction epitaxies with wide bandgap, high critical electric field as well as high density and high mobility two-dimensional electron gas have shown great potential applications in the next-generation high-power and high-frequency devices. Especially, with the development of Si-based GaN epitaxial technique with big size, GaN devices with low cost also show great advantage in consumer electronics. In order to improve the rectification efficiency of AlGaN/GaN Schottky barrier diode (SBD), low leakage current and low turn-on voltage are important. The GaN Schottky barrier diode with low work-function metal as anode is found to be very effective to reduce turn-on voltage. However, the low Schottky barrier height makes the Schottky interface sensitive to damage to groove surface, which leads to a high leakage current. In this work, a novel wet-etching technique with thermal oxygen oxidation and KOH corrosion is used to prepare the anode groove, and the surface roughness of groove decreases from 0.57 to 0.23 nm, compared with that of the dry-etching surface of groove. Meanwhile, the leakage current is suppressed from 1.5 × 10&lt;sup&gt;–6&lt;/sup&gt; to 2.6 × 10&lt;sup&gt;–7&lt;/sup&gt; A/mm. Benefiting from the great corrosion selectively of hot KOH solution to AlGaN barrier layer and GaN channel layer after thermal oxygen oxidation, the spikes of the edge of groove region caused by the nonuniform distribution of plasma in the cavity is improved, and the breakdown voltage of the fabricated AlGaN/GaN SBDs is raised from –1.28 to –1.73 kV.

Comparison of on-chip MIS capacitors based on stacked HfO2/Al2O3 nanolaminates

High- κ dielectric materials are commonly used in microelectronic components due to the technological necessity of increasing the capacitance density of dielectric layers. The thickness of the layer is a crucial parameter of this technology because it has a significant influence on dielectric properties, capacitance density, leakage current density–voltage ( J–V ), breakdown voltage, and capacitance density–voltage ( C–V ). Among metal oxide compounds, HfO 2 and Al 2 O 3 have been widely studied due to their good thermodynamic stability in contact with silicon. Thus, in this study, devices are fabricated by atomic layer deposition (ALD) processes on Si wafer. Properties of HfO 2 /Al 2 O 3 -based stack dielectric as on-chip MIS capacitors are investigated. The capacitance density, C–V , J–V , impedance characteristics, equivalent dielectric constant, breakdown voltage, and leakage current are studied on stacks (HfO 2 /Al 2 O 3 ) with a thickness ratio of 1:1. The experimental results indicate very good leakage current and good breakdown voltage. Oxygen vacancies play a significant role in increasing the conductance and contrarily decreasing the equivalent dielectric constant of the stack.

Characterization of ALD Ta2O5, Al2O3, and Ta2O5/Al2O3 Nanolaminate as Metal-Insulator-Metal Capacitor Dielectric for GaAs HBT Technology

In order to reduce die size and increase capacity, the metal-insulator-metal (MIM) capacitor area in circuit designs fabricated using GaAs hetero-junction bipolar transistor (HBT) technology has to be reduced. This can be achieved by using a capacitor dielectric material that has a high dielectric constant or high capacitance density. In GaAs HBT technology, the MIM capacitor dielectric film is typically also required to have a high breakdown voltage (>20 V) and low leakage current. Furthermore, the deposited dielectric film has to be compatible with GaAs processing and has to be deposited at a temperature of < 300oC, due to the limited process thermal budget in the HBT technology. As a result of these requirements, there are only a few materials available for MIM capacitor dielectric application in GaAs HBT technology.In this study, 60 nm tantalum pentoxide (Ta2O5), aluminum oxide (Al2O3), and Ta2O5/Al2O3 nanolaminate deposited using atomic layer deposition (ALD) have been characterized and evaluated as MIM capacitor dielectric for GaAs HBT technology. The results show that the capacitor with 60 nm of ALD Ta2O5 has the highest capacitance density (3.84x10-15 F/μm2), followed by the capacitor with 60 nm Ta2O5/Al2O3 nanolaminate, and the capacitor with 60 nm Al2O3 capacitor dielectric film with a capacitance density of 2.40x10-15 F/µm2 and 1.37x10-15 F/μm2, respectively. The calculated dielectric constant of ALD Ta2O5 and Ta2O5/Al2O3 nanolaminate is 26.1 and 16.3, respectively, while that of ALD Al2O3 is 9.3, as shown in Figure 1.Figure 2 shows the I-V characteristics of MIM capacitors with 4055 μm2 area and with 60 nm of ALD Ta2O5, Ta2O5/Al2O3 nanolaminate, and Al2O3 capacitor dielectric. As can be seen, the capacitor with Al2O3 capacitor dielectric has significantly lower leakage and higher breakdown voltage (46 V), while the capacitor with Ta2O5/Al2O3 and Ta2O5 capacitor dielectric has higher leakage current and lower breakdown voltage of 32.7 V and 22.4 V, respectively. Figure 3 shows the C-V characteristics of capacitors with the 3 ALD capacitor dielectric films. The results show that the capacitance of MIM capacitor using these three films increased marginally by 2.2% to 4.3%, when the temperature was increased from 25oC to 125oC. No significant change in capacitance density of these ALD capacitor dielectric films was observed, when the applied voltage was varied from -5 V to +5 V. Figure 1

Interface engineering of β-Ga2O3 MOS-type Schottky barrier diode using an ultrathin HfO2 interlayer

Low leakage current and high breakdown voltage are critically important to design high performance Schottky barrier diodes. In this work, a low leakage current was reported by studying the effect of inserting an ultrathin HfO2 layer using atomic-layer deposition with different cycle number at the interface between Ni and β-Ga2O3 for different annealing temperatures. A remarkable decrease in leakage current from 5.68 × 10−3 to 2.97 × 10−6 A/cm² at -300 V and a breakdown voltage increase from -467 to -556 V, were achieved when two cycles of HfO2 are inserted and annealed at 400°C. The leakage current decreases from 9.87 × 10−5 to 2.14 × 10−5 A/cm² for 200°C annealing temperature and from 1.035 × 10−4 to 2.56 × 10−6 A/cm² for as-deposited Metal-oxide semiconductor based Schottky barrier diode (MOSSBD) only after 2-cycles (∼2 Å) HfO2 is inserted. As the number of HfO2 cycles was increased (2–8 cycles) and the annealing temperature is varied, leakage current and breakdown voltage are affected. To investigate these variations in leakage current and breakdown voltage, Silvaco TCAD simulator is used. Good agreement is obtained between experiment and simulation by considering the fixed charge density in HfO2 (positive fixed charge density is related to oxygen vacancy density in HfO2 and the interfacial trap (reduced by annealing), and, where necessary, also considering the inhomogeneity of the Schottky barrier height to understand the main reason for the abrupt increase in leakage current at a specific reverse voltage.

High-Performance Lateral Avalanche Photodiode Based on Silicon-on-Insulator Structure

In this work, a silicon-on-insulator (SOI)-based lateral avalanche photodiode (APD) is proposed and fabricated. The device features lateral separate-absorption-multiplication (SAM) and electron-only injection. The bandwidth is optimized with the effective blocking of the deep photogenerated carriers by SOI structure. The device stability is also improved by additional shallow P-well region near the N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -region which can eliminate the edge breakdown induced by the curvature effect. Simulation results demonstrate that avalanche region (high electric field zone) is confined at the lateral PN <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> junction. Experimental fabrication and characterizations are further realized, and this SOI-based lateral APD device exhibits high responsivity (1.92 A/W at 7.8 V for 300 nm), low dark current (below 5 V), large bandwidth (12.4 GHz at 8.2 V), and low breakdown voltage (~7.8 V). The demonstrated device performance as well as the simple structure and good process compatibility can be attractive in future photo-detecting and advanced sensing applications.

A systematic study of the regrown interface impurities in unintentionally doped Ga-polar c-plane GaN and methods to reduce the same

Vertical gallium nitride (GaN) devices are strong candidates for next generation power electronics. Such vertical devices almost always require epitaxial regrowth of GaN. However, impurities present at the regrowth interfaces result in device degradation such as higher leakage current and lower breakdown voltage limiting its performance. While significant interface impurity concentration has been previously detected in the doped samples as well as in the etched-then-regrown samples, the origin of such interface impurity is still not well-understood. In this work, we perform a detailed characterization of the regrowth interface impurities of unintentionally doped (UID) Ga-polar GaN on c-plane sapphire substrate under various growth interruptions. This process (without any doping and without etch-then-regrowth) allows us to probe the relatively pristine regrown interface and thus better understand the origin of regrowth interface impurity. In the metal organic chemical vapor deposition (MOCVD) grown samples, we uncover a significant presence of silicon (Si) impurity concentration at the regrowth interface of an UID GaN for exposure both in air and in glovebox, with ∼88% higher impurity concentration for air exposure. This confirms an inevitable incorporation of Si impurities in the regrowth process originating from air, residual impurities in MOCVD environment and a further adsorption of impurities from the MOCVD chamber. We then demonstrate an ultraviolet (UV) ozone-based cleaning technique to reduce the concentration of Si impurities at the regrown interface. Using an iterative UV-ozone cleaning and wet etching treatment, we realize up to ∼61% reduction in the peak Si impurity concentrations therefore paving the way towards high performance vertical GaN devices.

Degradation Characteristics and Reliability Assessment of 1310 nm VCSEL for Microwave Photonic Link

The long-term reliability of the commercially available vertical-cavity surface-emitting laser (VCSEL) at 1310 nm wavelength is investigated. To do so, a high current accelerated life test is used to evaluate the 1310 nm VCSEL reliability. Variations of properties that depend on the operating condition are characterized by the light-current-voltage, leakage current and low-frequency noise. When the aging current is 6 mA, 8 mA and 10 mA, the maximum output power reduces by 5%, 6% and 15% of the initial value, respectively. It is demonstrated theoretically and experimentally that the leakage current increases and reverse bias breakdown voltage decreases after the accelerated current aging test. The current noise power spectral density increases after the device ages, and the noise increases with the augment of the electrical stress. When the bias current of VCSEL is below the threshold, the frequency index factor and noise amplitude gradually increase with the bias current increase. Further, lifetime fitting curves of the devices at an accelerating current of 6 mA, 8 mA and 10 mA are obtained, and the median lifetime of 67 years at the operating current is extrapolated.

β‐(Al0.17Ga0.83)2O3/Ga2O3 Delta‐Doped Heterostructure MODFETs with an Ultrathin Spacer Layer and a Back‐Barrier Layer: A Comprehensive Technology Computer‐Aided Design Analysis

The output characteristics of β‐(Al0.17Ga0.83)2O3/β‐Ga2O3‐based heterostructure modulation‐doped field‐effect transistors (MODFETs) with an ultrathin spacer layer and a back‐barrier layer are fitted with experimental measurements using a Silvaco ATLAS technology computer‐aided design (TCAD) simulation environment, and the calibration of the physical model and material parameters is realized. The effects of spacer layer thickness, barrier layer thickness, Si‐δ doping density, and insertion of a β‐Ga2O3 cap layer on the transfer and transconductance characteristics are examined. It is found that a β‐Ga2O3 cap layer on the top of the heterostructure can increase the sheet carrier density in the heterostructure. A breakdown analysis is also carried out to reveal the effects of several layers on the off‐state characteristics. A range of channel layer thicknesses from 15 to 25 nm is found to be the optimum range to avoid a high off‐state leakage current and earlier breakdown voltage.

Trap assisted charge transport and Schottky like conduction in CVD-grown amorphous SiC[formula omitted]O[formula omitted]-Si heterojunction

Silicon oxycarbide (SiCxOy), commonly used as low-κ inter layer dielectric in technological applications, is limited in performance due to dielectric breakdown in the presence of defect states. In this work, chemical vapour deposition technique has been used to fabricate carbon rich SiCxOy−n-silicon heterojunction using liquid polycarbosilane as precursor. The heterojunctions showed Schottky diode like behaviour with high current rectification (28k at ± 5 V) and high breakdown voltage (−100 V). Localised defect states originated from free residual carbon in deposited films, arising between valance band maxima and Fermi level of the oxycarbide, were found to be responsible for Schottky diode nature of the fabricated devices. A comprehensive band diagram of the heterojunction, alongside an insight of charge transport process, is presented based on valance band edge spectroscopy and temperature dependent transport measurements. A crossover between Zener and avalanche like soft breakdown was observed in our devices from which effective band gap of the oxycarbide films have been estimated. The devices showed excellent performance stability and reproducibility against rapid cyclic voltage sweep in ambient condition. Stability and performance reproducibility of the heterojunctions were remarkably maintained even after two years of storage in ambient condition that has long term implication in power electronics.

Leakage current suppression and breakdown voltage enhancement in GaN-on-GaN vertical Schottky barrier diodes enabled by oxidized platinum as Schottky contact metal

In this work, the oxidized metal PtO x was employed as the Schottky contact metal in the fabrication of gallium nitride (GaN)-on-GaN vertical Schottky barrier diodes (SBDs). Compared with the GaN SBD with just Pt Schottky anode, the Pt/PtO x /Pt-GaN SBDs exhibited a substantial reduction in reverse leakage current density from 5.2 × 10−6 A cm−2 to 5.6 × 10−9 A cm−2 (@ −50 V) and a large rise in the breakdown voltage () from 152 to 368 V, as well as maintaining the similar on-state characteristics in terms of turn-on voltage and on resistance. The temperature-dependent current–voltage characteristics of the fabricated devices further revealed that the Pt/PtO x /Pt-GaN SBDs possessed a higher Schottky barrier height and better high-temperature stability. Such an improvement should be attributed to the electric dipole effect in the PtO x layer. Moreover, the additional thin Pt layer between PtO x and GaN almost have no influence on the electric dipole effect of PtO x but can effectively protect the GaN surface from plasma damage and oxidation during the PtO x deposition. We believe that the proposed Pt/PtO x /Pt-GaN Schottky contact scheme provides a straightforward and effective strategy to develop next-generation GaN power electronic devices.

Metal-nitride dual-anode AlGaN/GaN heterostructure Schottky barrier diodes with tunable turn-on voltage and reverse leakage current

AlGaN/GaN heterostructure lateral Schottky barrier diodes (SBDs) with TiN and NiN dual anode (DA) on sapphire substrates are investigated in this letter. The NiN anode with its high work-function leads to low leakage current and high breakdown voltage, while TiN anode with its low work-function determines the low turn-on voltage of the DA SBDs. Tunable turn-on voltage and leakage current are obtained in the DA SBDs by varying the radius of the TiN anode. As the radius of the TiN anode decreases from 80 to 8 μm, the turn-on voltage increases from 0.64 to 0.94 V, while the reverse leakage current decreases from 1 × 10−2 to 1 × 10−4 mA mm−1 at a reverse bias of −10 V and cathode–anode distance of 20 μm. The differential specific on-resistance at 100 mA mm−1 is 4.5 mΩ cm2 and barely changes with various radius of the TiN anode. A high breakdown voltage of 1.49 kV is achieved in the AlGaN/GaN DA SBDs with the radius of 80 μm of the TiN anode, obtaining a power Baliga’s figure of merit of 0.48 GW cm−2 at the cathode–anode distance of 20 μm. Besides, dynamic on-resistance increases less than 15% under pulse voltage bias at −60 V which may account on the good interface between metal nitrides and AlGaN, which is beneficial to the high frequency and high power application.

A Review on Palm Oil-Based Nanofluids as a Future Resource for Green Transformer Insulation System

Alternative transformer oil has been investigated universally in past years. Different types of vegetable oil have been proposed and evaluated as replacements for conventional transformer oil (mineral oil) due to increasing exploitation and depleting petroleum reserves. In response to growing concern about global environmental and sustainable issues, this article discusses the suitability of palm oil (PO) and palm oil-based nanofluids (PO-N) as alternative transformer oils. A brief discussion of environmental concerns is provided in this paper, and the detailed properties of PO are thoroughly addressed. The electrical performance (alternating current breakdown voltage and lightning impulse breakdown voltage), physical behaviour (viscosity, flash point, and fire point), tan delta, and relative permittivity of PO and PO-N are also discussed in this paper. Based on reliable data and research, it has been proven that refined, bleached, deodorised palm oil (RBDPO) has been determined to be the most promising type of PO when compared to others. Furthermore, when CuO nanoparticles are added to RBDPO with the use of CTAB surfactant, the AC breakdown voltage increases by 173.42 % compared to RBDPO without CuO. However, there is still scope for further improvement in nanofluid stability. In addition to these studies, future research should focus on other aspects such as ageing studies, partial discharge breakdown voltage, etc. PO has interesting properties that make the industry and scientific community take notice.

Characterizations of a nanocomposite biochemical-sensing membrane of γ-APTES incorporated with silica nanoparticles prepared by ultrasonic liquid atomizer spray

Large-area and uniformly distributed 3-aminopropyltriethoxysilane (γ-APTES) incorporated with poly-dimethylsiloxane-treated hydrophobic fumed silica nanoparticles (NPs) sensing membranes with different mixed ratios were deposited by using ultrasonic liquid atomizer (ULA) spray. Nanoscale current–voltage (I–V) characteristics of the deposited membranes were then characterized by using conductive atomic force microscopy. It is found that the ULA-sprayed γ-APTES plus NPs (γ-APTES + NPs) membrane has smaller leakage current and higher breakdown voltage than does the ULA-sprayed pure γ-APTES membrane. Excellent glucose sensing performances are found when using the deposited ULA-sprayed γ-APTES + NPs as sensing membrane on polysilicon wire sensor. Further sensing performance enhancement was obtained as the γ-APTES + NPs membrane was subjected to UV illumination. Our experiment’s results confirmed that the ULA spray is a promising method for large area deposition of γ-APTES + NPs membrane and that it can be utilized for biomedical sensor applications.

Composite‐channel In 0. 17 Al 0 . 83 N /In 0. 1 Ga 0 . 9 N / GaN /Al 0. 04 Ga 0 . 96 N high electron mobility transistors for RF applications

In this work, we present the high performance of composite channel based In0.17Al0.83N/In0.1Ga0.9N/GaN/Al0.04Ga0.96N high electron mobility transistors (HEMTs) on a sapphire substrate. A numerical simulation is carried out for the proposed and conventional GaN channel-based HEMTs using TCAD. Due to the strong polarization of InAlN/InGaN, enhanced electron confinement and high electron mobility of composite channel based proposed device shows excellent DC and RF characteristics with improved linearity than conventional GaN channel based HEMTs. A 55 nm T-gate device demonstrates 4.45 A/mm drain current density (IDS) at VGS = 0 V, 0.7 S/mm stable transconductance (GM) for a wide range of gate bias, and excellent FT/Fmax of 274/288 GHz. Benefiting from the Al0.04Ga0.96N buffer (back-barrier), the device shows a very low sub-threshold drain leakage current and high breakdown voltage (VBR) of 43.5 V. The combination of high FT/Fmax, stable transconductance, and high breakdown voltage of the proposed HEMTs shows the great promise for high power and wide-bandwidth millimeter-wave applications.