Showing papers on "Gallium nitride published in 2013"

Gallium nitride devices for power electronic applications

Abstract: Recent success with the fabrication of high-performance GaN-on-Si high-voltage HFETs has made this technology a contender for power electronic applications. This paper discusses the properties of GaN that make it an attractive alternative to established silicon and emerging SiC power devices. Progress in development of vertical power devices from bulk GaN is reviewed followed by analysis of the prospects for GaN-on-Si HFET structures. Challenges and innovative solutions to creating enhancement-mode power switches are reviewed.

History of Gallium–Nitride-Based Light-Emitting Diodes for Illumination

Abstract: The history of development for gallium-nitride-based light-emitting diodes (LEDs) is reviewed. We identify two broad developments in GaN-based LED technology: first, the key breakthroughs that enabled the development of GaN-based devices on foreign substrates like sapphire (first-generation LEDs), and, second, a new wave of devices benefiting from developments in GaN substrate manufacturing, which has led to native bulk-GaN-based LEDs with unprecedented performance characteristics that portend a disruptive shift in LED output power density and the corresponding cost of generating light.

GaN on Si Technologies for Power Switching Devices

Abstract: This paper reviews the recent activities for normally-off GaN-based gate injection transistors (GITs) on Si substrates and their application to inverters. Epitaxial growth of the AlGaN/GaN heterostructures with good crystallinity over 200-mm Si substrates with eliminated bowing enables low-cost fabrication of GaN devices with high breakdown voltages. A novel normally-off GaN transistor called as GIT is proposed in which hole injection from the p-type AlGaN gate increases the drain current with low on-state resistance by conductivity modulation. The low on-state resistance in GaN-based devices greatly helps to increase the efficiency of power switching systems. A GaN-based three-phase inverter successfully drives a motor with high efficiency of 99.3% at a high output power of 1500 W. The presented GaN-based devices are expected to greatly help saving energy in the future as an indispensable power switching system.

Semipolar $({\hbox{20}}\bar{{\hbox{2}}}\bar{{\hbox{1}}})$ InGaN/GaN Light-Emitting Diodes for High-Efficiency Solid-State Lighting

Abstract: This work examines the effects of polarization-related electric fields on the energy band diagrams, wavelength shift, wave function overlap, and efficiency droop for InGaN quantum wells on various crystal orientations, including polar (0001) (c -plane), semipolar (2021), semipolar (2021), and nonpolar (1010) (m-plane). Based on simulations, we show that the semipolar (2021) orientation exhibits excellent potential for the development of high-efficiency, low-droop light-emitting diodes (LEDs). We then present recent advancements in crystal growth, optical performance, and thermal performance of semipolar (2021) LEDs. Finally, we demonstrate a low-droop, high-efficiency single-quantum-well blue semipolar (2021) LED with an external quantum efficiency of more than 50% at 100 A/cm2.

High Voltage Vertical GaN p-n Diodes With Avalanche Capability

Abstract: In this paper, vertical p-n diodes fabricated on pseudobulk gallium nitride (GaN) substrates are discussed. The measured devices demonstrate breakdown voltages of 2600 V with a differential specific on-resistance of 2 mΩ cm2. This performance places these structures beyond the SiC theoretical limit on the power device figure of merit chart. Contrary to common belief, GaN devices do possess avalanche capability. The temperature coefficient of the breakdown voltage is positive, showing that the breakdown is indeed because of impact ionization and avalanche. This is an important property of the device for operation in inductive switching environments. Critical electric field and mobility parameters for epitaxial GaN layers grown on bulk GaN are extracted from electrical measurements. The reverse recovery time of the vertical GaN p-n diode is not discernible because it is limited by capacitance rather than minority carrier storage, and because of this its switching performance exceeds the highest speed silicon diode.

Yellow luminescence of gallium nitride generated by carbon defect complexes.

Abstract: We demonstrate that yellow luminescence often observed in both carbon-doped and pristine GaN is the result of electronic transitions via the C(N)-O(N) complex. In contrast to common isolated defects, the C(N)-O(N) complex is energetically favorable, and its calculated optical properties, such as absorption and emission energies, a zero phonon line, and the thermodynamic transition level, all show excellent agreement with measured luminescence data. Thus, by combining hybrid density functional theory and experimental measurements, we propose a solution to a long-standing problem of the GaN yellow luminescence.

Improved heat dissipation in gallium nitride light-emitting diodes with embedded graphene oxide pattern

Abstract: The future of solid-state lighting relies on how the performance parameters will be improved further for developing high-brightness light-emitting diodes. Eventually, heat removal is becoming a crucial issue because the requirement of high brightness necessitates high-operating current densities that would trigger more joule heating. Here we demonstrate that the embedded graphene oxide in a gallium nitride light-emitting diode alleviates the self-heating issues by virtue of its heat-spreading ability and reducing the thermal boundary resistance. The fabrication process involves the generation of scalable graphene oxide microscale patterns on a sapphire substrate, followed by its thermal reduction and epitaxial lateral overgrowth of gallium nitride in a metal-organic chemical vapour deposition system under one-step process. The device with embedded graphene oxide outperforms its conventional counterpart by emitting bright light with relatively low-junction temperature and thermal resistance. This facile strategy may enable integration of large-scale graphene into practical devices for effective heat removal.

Analysis of Internal Quantum Efficiency and Current Injection Efficiency in III-Nitride Light-Emitting Diodes

Abstract: Current injection efficiency and internal quantum efficiency (IQE) in InGaN quantum well (QW) based light emitting diodes (LEDs) are investigated. The analysis is based on current continuity relation for drift and diffusion carrier transport across the QW-barrier systems. A self-consistent 6-band k ·p method is used to calculate the band structure for InGaN QW structure. Carrier-photon rate equations are utilized to describe radiative and non-radiative recombination in the QW and the barrier regions, carrier transport and capture time, and thermionic emission leading to carrier leakage out of the QW. Our model indicates that the IQE in the conventional 24-A In0.28Ga0.72 N -GaN QW structure reaches its peak at low injection current density and reduces gradually with further increase in current due to the large thermionic carrier leakage. The efficiency droop phenomenon at high current density in III-nitride LEDs is thus consistent with the high-driving-current induced quenching in current injection efficiency predicted by our model. The effects of the monomolecular recombination coefficient, Auger recombination coefficient and GaN hole mobility on the current injection efficiency and IQE are studied. Structures combining InGaN QW with thin larger energy bandgap barriers such as AlxGa1-xN, lattice-matched AlxIn1-xN, and lattice-matched AlxInyGa1-x-y N have been analyzed to improve current injection efficiency and thus minimize droop at high current injection in III-nitride LEDs. Effect of the thickness of the larger energy bandgap barriers (AlGaN, AlInN and AlInGaN) on injection efficiency and IQE are investigated. The use of thin AlGaN barriers shows slight reduction of quenching of the injection efficiency as the current density increases. The use of thin lattice-matched AlInN or AlInGaN barriers shows significant suppression of efficiency-droop in nitride LEDs.

High-Frequency High Power Density 3-D Integrated Gallium-Nitride-Based Point of Load Module Design

Abstract: The demand for the future power supplies that can achieve higher output currents, smaller sizes, and higher efficiencies cannot be satisfied with the conventional technologies. There are limitations in the switch performance, packaging parasitics, layout parasitics, and thermal management that must be addressed to push for higher frequencies and improved power density. To address these limitations, the utilization of Gallium-Nitride (GaN) transistors, 3-D integrated technique, low-profile magnetic substrates, and ceramic substrates with high thermal conductivity are considered. This paper discusses the characteristics of GaN transistors, including the fundamental differences between the enhancement mode and the depletion mode GaN transistors, gate driving, and the deadtime loss, the effect of parasitics on the performance of high-frequency GaN point-of-load (POLs), the 3-D copackage technique to integrate the active layer with low profile low temperature cofired ceramic magnetic substrate, and the thermal design of a high -density module using advanced substrates. The final demonstrators are three 12-1.2-V conversion POL modules: a single-phase 20 A 900 W/in3 2-MHz converter using enhancement mode GaN transistors, a single-phase10-A 800 W/in3 5-MHz converter, and a two-phase 20-A 1100 W/in3 5-MHz converter using the depletion mode GaN transistors. These converters offer unmatched power density compared to state-of-the-art industry products and research.

Lateral and Vertical Transistors Using the AlGaN/GaN Heterostructure

Abstract: Power conversion losses are endemic in all areas of electricity consumption, including motion control, lighting, air conditioning, and information technology. Si, the workhorse of the industry, has reached its material limits. Increasingly, the lateral AlGaN/GaN HEMT based on gallium nitride (GaN-on-Si) is becoming the device of choice for medium power electronics as it enables high-power conversion efficiency and reduced form factor at attractive pricing for wide market penetration. The reduced form factor enabled by high-efficiency operation at high frequency further enables significant system price reduction because of savings in bulky extensive passive elements and heat sink costs. The high-power market, however, still remains unaddressed by lateral GaN devices. The current and voltage demand for high power conversion application makes the chip area in a lateral topology so large that it becomes more difficult to manufacture. Vertical GaN devices would play a big role alongside of silicon carbide (SiC) to address the high power conversion needs. In this paper, the development, performance, and status of lateral and vertical GaN devices are discussed.

AlGaN/GaN-Based HEMTs Failure Physics and Reliability: Mechanisms Affecting Gate Edge and Schottky Junction

Abstract: This paper presents a comprehensive review of AlGaN/GaN high electron mobility transistor failure physics and reliability, focusing on mechanisms affecting the gate-drain edge, where maximum electric field and peak temperatures are reached. Physical effects at the origin of device degradation (inverse piezoelectric effect, time-dependent trap formation and percolative conductive paths formation, and electrochemical AlGaN and GaN degradation) are discussed on the basis of literature data and unpublished results. Thermally activated mechanisms involving metal-metal and metal-semiconductor interdiffusion at the gate Schottky junction are also discussed.

Current status and scope of gallium nitride-based vertical transistors for high-power electronics application

Abstract: Gallium nitride (GaN) is becoming the material of choice for power electronics to enable the roadmap of increasing power density by simultaneously enabling high-power conversion efficiency and reduced form factor. This is because the low switching losses of GaN enable high-frequency operation which reduces bulky passive components with negligible change in efficiency. Commercialization of GaN-on-Si materials for power electronics has led to the entry of GaN devices into the medium-power market since the performance-over-cost of even first-generation products looks very attractive compared to today's mature Si-based solutions. On the other hand, the high-power market still remains unaddressed by lateral GaN devices. The current and voltage demand for high-power conversion application makes the chip area in a lateral topology so large that it becomes difficult to manufacture. Vertical GaN devices would play a big role alongside silicon carbide (SiC) to address the high-power conversion needs. In this paper vertical GaN devices are discussed with emphasis on current aperture vertical electron transistors (CAVETs) which have shown promising performance. The fabrication-related challenges and the future possibilities enabled by the availability of good-quality, cost-competitive bulk GaN material are also evaluated for CAVETs.

AlGaN Channel HEMT With Extremely High Breakdown Voltage

Abstract: Enhanced performance of RF power modules is required in a next-generation information society. To satisfy these requirements, we designed a novel high-electron mobility transistor (HEMT) structure employing wider bandgap AlGaN for a channel layer, which we called AlGaN channel HEMT, and investigated it. The wider bandgap is more effective for higher voltage operation of HEMTs and contributes to the increase of output power in RF power modules. As a result, fabricated AlGaN channel HEMTs had much higher breakdown voltages than those of conventional GaN channel HEMTs with good pinchoff operation and sufficiently high drain current density without noticeable current collapse. Furthermore, specific on-state resistances of fabricated AlGaN channel HEMTs were competitive with the best values of reported GaN- and SiC-based devices with similar breakdown voltages. These results indicate that the proposed AlGaN channel HEMTs are very promising not only for an information-communication society but also in the power electronics field.

AlGaN/GaN HEMTs on Silicon Substrate With 206-GHz $F_{ \rm MAX}$

Abstract: This letter reports on AlGaN/GaN high-electron-mobility transistors (HEMTs) on high-resistive silicon substrate with a record maximum oscillation cutoff frequency FMAX. Double-T-shaped gates are associated with an optimized technology to enable high-efficiency 2-D electron gas control while mitigating the parasitic resistances. Good results ogate-length HEMTf FMAX = 206 GHz and FT = 100 GHz are obtained for a 90-nm gate-length HEMT with 0.25-μm source-to-gate spacing. The associated peak extrinsic transconductance value is as high as 440 mS·mm-1. To the authors' knowledge, the obtained FMAX and Gmext are the highest reported values for GaN HEMTs technology on silicon substrate. The accuracy of the cutoff frequency values is checked by small-signal modeling based on extracted S-parameters.

Evaluation and application of 600V GaN HEMT in cascode structure

Abstract: Gallium nitride high electron mobility transistor (GaN HEMT) has matured dramatically over the last few years. More and more devices have been manufactured and field in applications ranging from low power voltage regulator to high power infrastructure base-stations. Compared to the state of art silicon MOSFET, GaN HEMT has much better figure of merit and is potential for high frequency application. In general, 600V GaN HEMT is intrinsically normally-on device. To easily apply depletion mode GaN HEMT in circuit design, a low voltage silicon MOSFET is in series to drive the GaN HEMT, which is well known as cascode structure. This paper studies the characteristics and operation principles of 600V cascode GaN HEMT. Evaluations of GaN HEMT performance based on Buck converter under hard-switching and soft-switching conditions are presented. Experimental results illustrate that GaN HEMT is superior than silicon MOSFET but still needs soft-switching in high frequency operation due to considerable package and layout parasitic inductors and capacitors. Then GaN HEMT is applied to a 1MHz 300W 400V/12V LLC converter. Comparison of experimental results with state of art silicon MOSFET is provided to validate the advantages of GaN HEMT.

Nonadiabatic dynamics of positive charge during photocatalytic water splitting on GaN(10-10) surface: charge localization governs splitting efficiency.

Abstract: Photochemical water splitting is a promising avenue to sustainable, clean energy and fuel production. Gallium nitride (GaN) and its solid solutions are excellent photocatalytic materials; however, the efficiency of the process is low on pure GaN, and cocatalysts are required to increase the yields. We present the first time-domain theoretical study of the initial steps of photocatalytic water splitting on a GaN surface. Our state-of-the-art simulation technique, combining nonadiabatic molecular dynamics and time-dependent density functional theory, allows us to characterize the mechanisms and time scales of the evolution of the photogenerated positive charge (hole) and the subsequent proton transfer at the GaN/water interface. The calculations show that the hole loses its excess energy within 100 fs and localizes primarily on the nitrogen atoms of the GaN surface, initiating a sequence of proton-transfer events from the surface N–H group to the nearby OH groups and bulk water molecules. Water splitting re...

High-Breakdown-Voltage and Low-Specific-on-Resistance GaN p-n Junction Diodes on Free-Standing GaN Substrates Fabricated Through Low-Damage Field-Plate Process

Abstract: In this letter, we describe the characteristics of Gallium Nitride (GaN) p–n junction diodes fabricated on free-standing GaN substrates with low specific on-resistance Ron and high breakdown voltage VB. The breakdown voltage of the diodes with the field-plate (FP) structure was over 3 kV, and the leakage current was low, i.e., in the range of 10-4 A/cm2. The specific on-resistance of the diodes of 60 µm diameter with the FP structure was 0.9 mΩcm2. Baliga's figure of merit (VB2/Ron) of 10 GW/cm2 is obtained. Although a certain number of dislocations were included in the device, these excellent results indicated a definite availability of this material system for power-device applications.

High-Voltage (600-V) Low-Leakage Low-Current-Collapse AlGaN/GaN HEMTs with AlN/SiN x Passivation

Abstract: An effective passivation technique that yields low off-state leakage and low current collapse simultaneously in high-voltage (600-V) AlGaN/GaN high-electron-mobility transistors (HEMTs) is reported in this letter. The passivation structure consists of an AlN/SiNx stack with 4-nm AlN deposited by plasma-enhanced atomic layer deposition and 50-nm SiNx deposited by PECVD. The AlN/ SiNx-passivated HEMTs with a gate-drain distance of 15 μm exhibit a high maximum drain current of 900 mA/mm, a low off-state current of 0.7 μA/mm at VDS = 600 V, and a steep subthreshold slope of 63 mV/dec. Compared with the static on-resistance of 1.3 mΩ·cm2, the dynamic on-resistance after high off-state drain bias stress at 650 V only increases to 2.1 mΩ·cm2. A high breakdown voltage of 632 V is achieved at a drain leakage current of 1 μA/mm .

Evaluation of 600 V cascode GaN HEMT in device characterization and all-GaN-based LLC resonant converter

Abstract: In recent years, Si power MOSFET is approaching its performance limits, and Gallium Nitride (GaN) HEMT is getting mature. This paper evaluates the 600 V cascode GaN HEMT performance, and compares it with the state-of-the-art Si CoolMOS in LLC resonant converter. First, the static characterization of 600 V cascode GaN HEMT is described in different temperatures. The switching performance is tested by a double pulse tester to provide the turn-off loss reference to the design of LLC resonant converter. Second, a 400 V-12 V/300 W/1 MHz all-GaN-based converter with the 600 V cascode GaN HEMT is compared with a Si-based converter with the 600 V Si CoolMOS. The device output capacitance is a key factor in the design and loss analysis of LLC resonant converter. The design results show that the total GaN device loss of the all-GaN-based converter can be improved by 42% compared with the total Si device loss. Finally, both 400 V-12 V/300 W/1 MHz Si-based and GaN-based LLC resonant converter prototypes are tested and compared with waveforms and efficiency curves.

Nonlinear Electrothermal GaN HEMT Model Applied to High-Efficiency Power Amplifier Design

Abstract: Gallium Nitride (GaN) high electron-mobility transistors (HEMTs) can operate at very high power-density levels, which may cause a significant temperature rise in the transistor channel. In addition, surface and substrate energy levels, or “traps,” can cause strong dispersion effects from pulsed I-V down to dc timescales. Such effects, for both simulation accuracy and device reliability purposes, must be accounted for in any nonlinear device model. In this paper, a novel nonlinear high-power GaN HEMT equivalent circuit electrothermal model is described. Features of the model include a nonlinear thermal subnetwork that is capable of capturing the well-known inherent nonlinear thermal resistance and capacitance of GaN material. Also included is a comprehensive dispersion model that can be extracted and modeled from simple measurements. The model can very accurately predict the pulsed I -V curves at different pulse widths and duty cycles from isothermal up to the safe-operating area limit. Large-signal one-tone, two-tone, and frequency sweep tests show excellent agreement with measurements. Finally, a continuous class-F amplifier is fabricated, and large-signal frequency sweeps are performed. Comparison between the measured and modeled amplifier metrics demonstrate that the model remains accurate over a 50% bandwidth under real-world conditions.

Power Electronic Devices in the Future

Abstract: This paper discusses extrapolations of current silicon power device technology into the future, followed by discussions of wide band gap (WBG) power devices with a focus on silicon carbide and gallium nitride. Other WBG materials are included from carbon, such as diamond and nanotubes, to various nitrides. Far future material development, that may impact power electronic devices decades out, is also discussed.

Trapping phenomena in AlGaN/GaN HEMTs: a study based on pulsed and transient measurements

Abstract: Slow trapping phenomenon in AlGaN/GaN HEMTs has been extensively analyzed and described in this paper. Thanks to a detailed investigation, based on a combined pulsed and transient investigation of the current/voltage characteristics (carried out over on an 8-decade time scale), we report a detailed description of the properties of trap levels located in the gate–drain surface, and in the region under the gate of AlGaN/GaN HEMTs. More specifically, the following, relevant results have been identified: (i) the presence of surface trap states may determine a significant current collapse, and reduction of the peak transconductance. During a current transient measurement, the emission of electrons trapped at surface states proceeds through hopping, as demonstrated by means of temperature-dependent measurements. The activation energy of the de-trapping process is equal to 99 meV. (ii) The presence of a high density of defects under the gate may induce a significant shift in the threshold voltage, when devices are submitted to pulsed transconductance measurements. The traps responsible for this process have an activation energy of 0.63 eV, and are detected only on samples with high gate leakage, since gate current allows for a more effective charging/de-charging of the defects.

On-chip optical interconnects made with gallium nitride nanowires.

Abstract: In this Letter we report on the fabrication, device characteristics, and optical coupling of a two-nanowire device comprising GaN nanowires with light-emitting and photoconductive capabilities. Axial p–n junction GaN nanowires were grown by molecular beam epitaxy, transferred to a non-native substrate, and selectively contacted to form discrete optical source or detector nanowire components. The optical coupling demonstrated for this device may provide new opportunities for integration of optical interconnects between on-chip electrical subsystems.

History of GaN: High-Power RF Gallium Nitride (GaN) from Infancy to Manufacturable Process and Beyond

Abstract: In the early 1990s, gallium nitride (GaN) was deemed an excellent, next generation, semiconductor material for high power/high frequency transistors based on the material parameters of bandgap, electron mobility, and saturated electron velocity (Figure 1). The lack of bulk GaN source material led to the need for GaN growth on mismatched substrates such as Si, SiC and sapphire, but fundamental material development controlled the pace of maturation of GaN technology for both electronic and optoelectronic applications [1]. The development of GaN for RF electronics was significantly aided by the intense development that occurred in the race to first production of blue and, eventually, white light-emitting diodes (LEDs). Ultimately, advancements in the growth of device-grade aluminum gallium nitride (AlGaN)/GaN

A new method for the synthesis of epitaxial layers of silicon carbide on silicon owing to formation of dilatation dipoles

Abstract: A new method is developed for the solid-phase synthesis of epitaxial layers when the substrate itself is involved into a chemical reaction and the reaction product grows in the interior of substrate layer. It opens up new possibilities for the relaxation of the elastic energy due to attraction of point defects formed during the chemical reaction in anisotropic media. In the same time, the attracting point dilatation centers compose relatively stable formations—dilatation dipoles, named by analogy with electric dipoles, providing significant reduction of the total elastic energy. The correspondent theory of interaction of point dilatation centers in anisotropic crystals is developed. It is eliminated that the most advantageous location of the dipoles is the direction (111) in crystals with cubic symmetry. In order to confirm the theory, the single-crystal silicon carbide films with the thickness up to 200 nm have been grown on silicon (111) substrates owing to the chemical reaction with carbon monoxide. Grown high-quality single-crystal silicon carbide films do not contain misfit dislocations despite the huge lattice mismatch value of ∼20%. Also the possibility of growing of thick wide-gap semiconductor films on such templates SiC/Si(111) and, accordingly, its integration into silicon electronics, is demonstrated. In particular, a working LED structure based on gallium nitride has been produced. Finally, the thermodynamic theory of new phase nucleation due to a chemical reaction has been developed and it was shown that in the case under consideration the chemical equilibrium constant generalizes the concentration of adatoms exploited in a one-component nucleation theory.

Epitaxial GaN Microdisk Lasers Grown on Graphene Microdots

Abstract: Direct epitaxial growth of inorganic compound semiconductors on lattice-matched single-crystal substrates has provided an important way to fabricate light sources for various applications including lighting, displays and optical communications. Nevertheless, unconventional substrates such as silicon, amorphous glass, plastics, and metals must be used for emerging optoelectronic applications, such as high-speed photonic circuitry and flexible displays. However, high-quality film growth requires good matching of lattice constants and thermal expansion coefficients between the film and the supporting substrate. This restricts monolithic fabrication of optoelectronic devices on unconventional substrates. Here, we describe methods to grow high-quality gallium nitride (GaN) microdisks on amorphous silicon oxide layers formed on silicon using micropatterned graphene films as a nucleation layer. Highly crystalline GaN microdisks having hexagonal facets were grown on graphene dots with intermediate ZnO nanowalls via epitaxial lateral overgrowth. Furthermore, whispering-gallery-mode lasing from the GaN microdisk with a Q-factor of 1200 was observed at room temperature.

III-Nitride Semiconductors and Their Modern Devices

Abstract: 1. Development of the nitride-based UV/DUV LEDs 2. The homoepitaxial challenge: GaN crystals grown at high pressure for laser diodes and laser diode arrays 3. Epitaxial growth and benefits of GaN on silicon 4. The growth of bulk aluminum nitride 5. Epitaxial growth of nitride quantum dots 6. Properties of InAlN layers nearly lattice-matched to GaN and their use for photonics and electronics 7. Growth and optical properties of aluminum rich AlGaN heterostructures 8. Optical and structural properties of InGaN light emitters on non- and semipolar GaN 9. GaN-based single-nanowire devices 10. Advanced photonic and nanophotonic devices 11. Nitride-based electron devices for high power / high frequency applications 12. Intersubband transitions in low dimensional nitrides 13. The slow light in gallium nitride 14. Nitride devices and their biofunctionalization for biosensing applications 15. Heterovalent ternary II-IV-N2 compounds: perspectives for a new class of wide-band-gap nitrides 16. Terahertz emission in polaritonic systems with nitrides

Enhanced AlGaN/GaN MOS-HEMT Performance by Using Hydrogen Peroxide Oxidation Technique

Abstract: This paper investigates enhanced device characteristics of AlGaN/GaN metal-oxide-semiconductor high electron mobility transistor (HEMT) (MOS-HEMT) fabricated by using hydrogen peroxide (H2O2) oxidation technique which demonstrates the advantages of simplicity and cost effectiveness. A 13-nm-thick Al2O3 oxide was grown upon the surface of AlGaN barrier layer and served as the gate dielectric layer and the surface passivation layer at the same time to effectively decrease gate leakage current and prevent RF current collapse, which are the critical issues of nitride HEMTs. Enhanced device performances of dc, RF, power, and reliability of the present MOS-HEMT are comprehensively investigated as compared with a conventional Schottky-gate HEMT.