Gallium Nitride High Electron Mobility Research Articles

Numerical simulation and microchannels parameters optimization for thermal management of GaN HEMT devices

PurposeThis study aims to satisfy the thermal management of gallium nitride (GaN) high-electron mobility transistor (HEMT) devices, microchannel-cooling is designed and optimized in this work.Design/methodology/approachA numerical simulation is performed to analyze the thermal and flow characteristics of microchannels in combination with computational fluid dynamics (CFD) and multi-objective evolutionary algorithm (MOEA) is used to optimize the microchannels parameters. The design variables include width and number of microchannels, and the optimization objectives are to minimize total thermal resistance and pressure drop under constant volumetric flow rate.FindingsIn optimization process, a decrease in pressure drop contributes to increase of thermal resistance leading to high junction temperature and vice versa. And the Pareto-optimal front, which is a trade-off curve between optimization objectives, is obtained by MOEA method. Finally, K-means clustering algorithm is carried out on Pareto-optimal front, and three representative points are proposed to verify the accuracy of the model.Originality/valueEach design variable on the effect of two objectives and distribution of temperature is researched. The relationship between minimum thermal resistance and pressure drop is provided which can give some fundamental direction for microchannels design in GaN HEMT devices cooling.

GaN-HEMT Based Very-High-Frequency AC Power Supply for Electrosurgery.

To power electrosurgery, a very-high-frequency AC inverter (VHFI) is required. In this paper, a full-bridge based VHFI is proposed to enable electrosurgery. Its high-frequency output generating mechanism and the high order filter design are explained. To check the feasibility of the proposed VHFI, a 300 W Gallium Nitride High Electron Mobility Transistors (GaN HEMT) based experimental setup with 390 kHz output frequency, has been designed and implemented. Experimental efficiency and total harmonic distortion (THD) results are graphed for pure cutting mode. It turns out that maximum THD is less than 2.5% for the proposed VHFI. Further, recurring and burst experiment results are provided for blend cutting mode and coagulation mode, respectively. The experiment results show that the proposed VHFI has extreme fast-responding time for both blend cutting and coagulation mode, and crest factor is about 21 for coagulation mode. All experiment results together validate the feasibility of the proposed VHFI and also verify its capability of supporting different load values under different clinical modes.

Computational Analysis of Joule Heating Effect in Triple Material Gate AlGaN/GaN High Electron Mobility Transistor

Aluminum gallium nitride (AlGaN)/gallium nitride (GaN) high electron mobility transistor (HEMT) has shown great potential and superiority over other devices in high power and high speed-based systems [1-4]. Recently, a novel AlGaN/GaN HEMT structure named triple material gate (TMG) HEMT has been proposed in [5] in which the gate contact is composed of three metals with different work functions. TMG HEMT ensures high carrier velocity and better suppression of short channel effects. In this work, a two-dimensional electro-thermal model has been developed to investigate the joule heating effect in TMG AlGaN/GaN HEMT using the software COMSOL [6]. The current continuity and heat transport equations are solved self-consistently to obtain the temperature distribution profile in various layers of the device. Thermal efficiency of TMG HEMT is compared with dual material gate and single material gate HEMT. It has been found that, besides providing better current carrying capability, TMG HEMT shows optimum thermal performance. Moreover, the variation of peak temperature in the channel with drain and gate voltages is analyzed to study the bias voltage dependence of the device temperature rise. Effects of several device parameters like total channel length, spontaneous and piezoelectric polarization induced charges and ratio of lengths of control and screen gates, on the thermal performance have also been explored. Simulations are carried out for the device lying on different substrate materials (Sapphire, GaN, Si and SiC) with varying thermal conductivity to demonstrate their performance in heat removal capacity. This simulation model can serve as a very useful tool to comprehend the thermal behavior of the device for high power and high frequency applications.

Computational Analysis of Joule Heating Effect in Triple Material Gate AlGaN/GaN High Electron Mobility Transistor

A two-dimensional electro-thermal model has been developed to investigate the Joule heating effect in triple material gate (TMG) aluminum gallium nitride (AlGaN) / gallium nitride (GaN) high electron mobility transistor (HEMT) using the software COMSOL. The current continuity and heat transport equations are solved self-consistently to obtain the temperature distribution profile in various layers of the device. By comparing with dual material gate and single material gate HEMTs, it has been found that, besides providing better current carrying capability, TMG HEMT shows optimum thermal performance. Effects of several device parameters like total channel length, spontaneous and piezoelectric polarization induced charges and ratio of lengths of control and screen gates, on the thermal efficiency have been explored. Bias voltage and underlying substrate material dependence of the device operation have also been investigated.

Design of X-band SSPA based on GaN HEMT for telemetry subsystem of near-earth space missions

In this paper, the design, and implementation of an X-band, 10 W, Solid-State Power Amplifier (SSPA) based on Hybrid Microwave Integrated Circuit (HMIC) technology using Gallium Nitride (GaN) High-Electron Mobility Transistor (HEMT) dies for near-earth space applications is presented. Designed SSPA is customized for use in suborbital missions and has two stages. We have used narrowband Transmission Lines (TL) class E architecture for designing the proposed SSPA. We have applied the transconductance tuning technique for the first time to a GaN HMIC for achieving the required linearity without any additional circuits. Hybrid optimization helps us for obtaining the best output power, efficiency, and linearity in comparison to other X-band GaN HMICs. We implemented our design with a Rogers 6010 laminate printed circuit board (PCB) on a Cu plate for improving the thermal heat transfer. All the on-chip pads were bonded to PCB using gold bonding wires with 25-µm diameter directly. We obtained 40 dBm and 37 dBm maximum output power in the saturation and 1-dB compression point, respectively. The central frequency of the proposed SSPA is 10,640 MHz with 150 MHz Band Width (BW). It works in EB-class with a 40 V voltage power supply and has more than 40% efficiency in saturation output power (Psat). We obtained two tones Intermodulation Distortion Third Harmonic (IMD3) better than −17 dBc in-band. The active area of the implemented SSPA is 40 mm × 50 mm.

Eighty nine‐watt cascaded multistage power amplifier using gallium nitride‐on‐silicon high electron mobility transistor for L‐band radar applications

This work presents a gallium nitride (GaN) high electron mobility transistor (HEMT)–based cascaded multistage power amplifier (MPA) in class-AB for L-band radar applications. The purpose of this endeavour is to develop an MPA using GaN HEMT devices to achieve optimised parameters such as high gain, high power, better efficiency, and linearity in a compact size. In an MPA design with multiple stages, oscillations are common owing to unwanted high gain at the lower frequency range. To overcome this issue, we introduced interstage harmonic termination networks as a novel approach to suppress high gain at low frequencies, which are prone to oscillations. The proposed cascaded MPA provides the maximum radio-frequency output power of 89 W and a power gain of 52 dB with an associated power-added efficiency of 51%. Second and third harmonic levels are −32.5 and −37 dBc, respectively. Two-tone measurements are performed with a frequency separation of 10 MHz, and an intermodulation level of less than −33 dBc is achieved.

Investigation on GaN HEMTs Based Three-Phase STATCOM with Hybrid Control Scheme.

The modern trend of decarbonization has encouraged intensive research on renewable energy (RE)-based distributed power generation (DG) and smart grid, where advanced electronic power interfaces are necessary for connecting the generator with power grids and various electrical systems. On the other hand, modern technologies such as Industry 4.0 and electrical vehicles (EV) have higher requirements for power converters than that of conventional applications. Consequently, the enhancement of power interfaces will play an important role in the future power generation and distribution systems as well as various industrial applications. It has been discovered that wide-bandgap (WBG) switching devices such as gallium nitride (GaN) high electron mobility transistors (HEMTs) and silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) offer considerable potential for outperforming conventional silicon (Si) switching devices in terms of breakdown voltage, high temperature capability, switching speed, and conduction losses. This paper investigates the performance of a 2kVA three-phase static synchronous compensator (STATCOM) based on a GaN HEMTs-based voltage-source inverter (VSI) and a neural network-based hybrid control scheme. The proportional-integral (PI) controllers along with a radial basis function neural network (RBFNN) controller for fast reactive power control are designed in synchronous reference frame (SRF). Both simulation and hardware implementation are conducted. Results confirm that the proposed RBFNN assisted hybrid control scheme yields excellent dynamic performance in terms of various reactive power tracking control of the GaN HEMTs-based three-phase STATCOM system.

Minimum Power Input Control for Class-E Amplifier Using Depletion-Mode Gallium Nitride High Electron Mobility Transistor

In this study, we implemented a depletion (D)-mode gallium nitride high electron mobility transistor (GaN HEMT, which has the advantage of having no body diode) in a class-E amplifier. Instead of applying a zero voltage switching control, which requires high frequency sampling at a high voltage (>600 V), we developed an innovative control method called the minimum power input control. The output of this minimum power input control can be presented in simple empirical equations allowing the optimal power transfer efficiency for 6.78 MHz resonant wireless power transfer (WPT). In order to reduce the switching loss, a gate drive design for the D-mode GaN HEMT, which is highly influential for the reliability of the resonant WPT, was also produced and described here for circuit designers.

Frequency-Locked RF Power Oscillator With 43-dBm Output Power and 58% Efficiency

This article presents the frequency-locked high-power RF oscillator using a gallium nitride (GaN) high electron mobility transistor (HEMT) amplifier and phase-locked loop (PLL) for 2.4-GHz industrial, scientific, and medical (ISM) band applications. The proposed architecture exploits the GaN power amplifier in the positive-feedback loop, whereas the desired phase shift for the target oscillating frequency is regulated from the PLL. To the best of our knowledge, this work is the first to employ the frequency locking scheme for a high-power solid-state RF oscillator. A detailed analysis of the oscillation conditions and the efficiency is provided. The prototype circuit is implemented with hybrid phase shifters and a fractional- N frequency synthesizer. The implemented RF oscillator circuit operates from 2.3 to 2.575 GHz and achieves a low phase noise of -131.8 dBc/Hz at a 1-MHz offset frequency. The power efficiency of the proposed oscillator reaches 58%, and the PLL incurs only 0.2% efficiency degradation.

GaN-Based Multiple Output Flyback Converter With Independently Controlled Outputs

Several techniques are proposed in the literature to improve the cross-regulation performance of a multiple output flyback converter (MOFC). However, some drawbacks exist, first, inability to completely eliminate cross-regulation, second, reduction of power density due to a high number of additional components, third, increased losses. To overcome these challenges, this article presents a scheme to independently control the outputs of an MOFC, thereby achieving an excellent cross-regulation performance over a wide range of loads, without any additional switching or magnetic component. The unique gate dependent reverse conduction characteristics of gallium nitride (GaN) high electron mobility transistor is utilized to control the flow of current to each of the output capacitors. The operational principle and the steady-state analysis are provided in detail. Moreover, design considerations, such as the switching frequency, GaN gate bias, leakage inductances, and output capacitance, are discussed, focusing on their impacts on the key design goals, particularly the efficiency, power density, and output voltage ripple. Furthermore, SPICE simulations are used to demonstrate the improvement in cross-regulation over existing schemes. Finally, a 40 W dual output laboratory prototype is built to verify the analysis. The measured maximum cross-regulation is 0.2%, which validates the effectiveness of the scheme.

A 5-Bit X-Band GaN HEMT-Based Phase Shifter

In this study, we propose a 5-bit X-band gallium nitride (GaN) high electron mobility transistor (HEMT)-based phased shifter monolithic microwave integrated circuit for a phased-array technique. The design includes high-pass/low-pass networks for the 180° phase bit, two high-pass/bandpass networks separated for the 45° and 90° phase bits, and two transmission lines based on traveling wave switch and capacitive load networks that are separated for the 11.25° and 22.5° phase bits. The state-to-state variation in the insertion loss is 11.8 ± 3.45 dB, and an input/output return loss of less than 8 dB was obtained in a frequency range of 8–12 GHz. Moreover, the phase shifter achieved a low root mean square (RMS) phase error and RMS amplitude error of 6.23° and 1.15 dB, respectively, under the same frequency range. The measured input-referred P1dB of the five primary phase shift states were larger than 29 dBm at 8 GHz. The RMS phase error and RMS amplitude error slightly increased when the temperature increased from 25 to 100 °C. The on-chip phase shifter exhibited no dc power consumption and occupied an area of 2 × 3 mm2.

2.4 GHz GaN HEMT Class-F Synchronous Rectifier Using an Independent Second Harmonic Tuning Circuit.

This paper proposes a class-F synchronous rectifier using an independent second harmonic tuning circuit for the power receiver of 2.4 GHz wireless power transmission systems. The synchronous rectifier can be designed by inverting the RF output port to the RF input port of the pre-designed class-F power amplifier based on time reversal duality. The design of the class-F power amplifier deploys an independent second harmonic tuning circuit in the matching networks to individually optimize the impedances of the fundamental and the second harmonic. The synchronous rectifier at the 2.4 GHz frequency is designed and implemented using a 6 W gallium nitride high electron mobility transistor (GaN HEMT). Peak RF-dc conversion efficiency of the rectifier of 69.6% is achieved with a dc output power of about 7.8 W, while the peak drain efficiency of the class-F power amplifier is 72.8%.

The Study of the Single Event Effect in AlGaN/GaN HEMT Based on a Cascode Structure

An attractive candidate for space and aeronautic applications is the high-power and miniaturizing electric propulsion technology device, the gallium nitride high electron mobility transistor (GaN HEMT), which is representative of wide bandgap power electronic devices. The cascode AlGaN/GaN HEMT is a common structure typically composed of a high-voltage depletion-mode AlGaN/GaN HEMT and low-voltage enhancement-mode silicon (Si) MOSFET connected by a cascode structure to realize its enhancement mode. It is well known that low-voltage Si MOSFET is insensitive to single event burnout (SEB). Therefore, this paper mainly focuses on the single event effects of the cascode AlGaN/GaN HEMT using technical computer-aided design (TCAD) simulation and heavy-ion experiments. The influences of heavy-ion energy, track length, and track position on the single event effects for the depletion-mode AlGaN/GaN HEMT were studied using TCAD simulation. The results showed that a leakage channel between the gate electrode and drain electrode in depletion-mode AlGaN/GaN HEMT was formed after heavy-ion striking. The enhancement of the ionization mechanism at the edge of the gate might be an important factor for the leakage channel. To further study the SEB effect in AlGaN/GaN HEMT, the heavy-ion test of a cascode AlGaN/GaN HEMT was carried out. SEB was observed in the heavy-ion irradiation experiment and the leakage channel was found between the gate and drain region in the depletion-mode AlGaN/GaN HEMT. The heavy-ion irradiation experimental results proved reasonable for the SEB simulation for AlGaN/GaN HEMT with a cascode structure.

Impact of E‐Mode Gallium Nitride High Electron Mobility Transistor with P‐Type Gate on Waveform Distortion in an AirFuel Wireless Power Transfer System

Wireless Power Transfer In article number 2000565 by Yufeng Jin and co-workers the reliability of GaN device in wireless power transfer system is studied. The wireless power transfer system module is at the bottom left of the picture. The authors study the reliability of the device in the system from two directions, device-level and circuit-level. The GaN device’s structure is shown at bottom right of the cover image. In the small circle is the band structure of the device, which reflects the cause of the reliability issues (such as trap, tunneling). Upper of the picture is the schematic diagram of the wireless power transfer. According to adjust the operation condition of the system, the reliability of the device can be improved.

GaN МИС малошумящего усилителя Х-диапазона

The purpose of this paper is to design a microwave monolithic integrated circuit (MMIC) for low noise amplifier (LNA) X-band (7-12 GHz) based on technology of gallium nitride (GaN) high electron mobility transistor (HEMT) with a T-gate, which has 100 nm width, on a silicon (Si) semi-insulating substrate of the OMMIC company. The amplifier is based on common-source transistors with series feedback, which was formed by high-impedance transmission line, and with parallel feedback to match noise figure and power gain. The key characteristics of an LNA are noise figure and gain. However, in this paper, it was decided to design the LNA, which should have a good margin in terms of input and output power. As a result, GaN technology was chosen, which has a higher noise figure compared to other technologies, but eliminates the need for an input power limiter, which in turn significantly increases the overall noise figure. As a result LNA MMIC was developed with the following characteristics: noise figure less than 1.6 dB, small-signal gain more than 20 dB, return loss better than -13 dB and output power more than 19 dBm with 1 dB compression in the range from 7 to 12 GHz in dimensions 2x1.5 mm², which has a supply voltage of 8 V and a current consumption of less than 70 mA. However, it should be said that LNA was only modeled in the AWR DE.

Trapping Dynamics in GaN HEMTs for Millimeter-Wave Applications: Measurement-Based Characterization and Technology Comparison

Charge trapping effects represent a major challenge in the performance evaluation and the measurement-based compact modeling of modern short-gate-length (i.e., ≤0.15 μm) Gallium Nitride (GaN) high-electron mobility transistors (HEMT) technology for millimeter-wave applications. In this work, we propose a comprehensive experimental methodology based on multi-bias large-signal transient measurements, useful to characterize charge-trapping dynamics in terms of both capture and release mechanisms across the whole device safe operating area (SOA). From this dataset, characterizations, such as static-IV, pulsed-IV, and trapping time constants, are seamlessly extracted, thus allowing for the separation of trapping and thermal phenomena and delivering a complete basis for measurement-based compact modeling. The approach is applied to different state-of-the-art GaN HEMT commercial technologies, providing a comparative analysis of the measured effects.

Review on Driving Circuits for Wide-Bandgap Semiconductor Switching Devices for Mid- to High-Power Applications.

Wide-bandgap (WBG) material-based switching devices such as gallium nitride (GaN) high electron mobility transistors (HEMTs) and silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) are considered very promising candidates for replacing conventional silicon (Si) MOSFETs for various advanced power conversion applications, mainly because of their capabilities of higher switching frequencies with less switching and conduction losses. However, to make the most of their advantages, it is crucial to understand the intrinsic differences between WBG- and Si-based switching devices and investigate effective means to safely, efficiently, and reliably utilize the WBG devices. This paper aims to provide engineers in the power engineering field a comprehensive understanding of WBG switching devices’ driving requirements, especially for mid- to high-power applications. First, the characteristics and operating principles of WBG switching devices and their commercial products within specific voltage ranges are explored. Next, considerations regarding the design of driving circuits for WBG switching devices are addressed, and commercial drivers designed for WBG switching devices are explored. Lastly, a review on typical papers concerning driving technologies for WBG switching devices in mid- to high-power applications is presented.

Optimized Broadband Load Network for Doherty Power Amplifier Based on Bandwidth Balancing

This letter presents an optimized broadband load network for the Doherty power amplifier (DPA) based on bandwidth balancing between low- and peak-power levels. The optimized broadband load network is composed of a quasi-lumped $\lambda $ /4 impedance transformer (ITF), a modified multiple resonance circuit (MMRC), and a broadband postmatching network (PMN). The quasi-lumped ITF at the carrier amplifier has an optimized characteristic impedance for bandwidth balancing between low- and peak-power levels. The MMRC provides the quasi-lumped ITF with an appropriate susceptance for optimized bandwidth. It also matches the impedance for the peaking amplifier. To validate this design concept, the broadband DPA was implemented using 30-W gallium–nitride high electron mobility transistor (GaN-HEMT) for both carrier and peaking amplifiers. For the down-link long-term evolution (LTE) signal with a channel bandwidth of 10 MHz and a peak-to-average power ratio (PAPR) of 6.5 dB at the frequency range of 1.15–2.45 GHz, DE ranging from 38.4% to 52.2%, and the adjacent channel leakage power ratio (ACLR) ranging from −23.9 to −35.0 dBc at an average output power of from 39.7 to 41.7 dBm were achieved.

Modeling and Analysis of Double Channel GaN HEMTs Using a Physics-Based Analytical Model

In this work, we report the development of a new physics-based analytical model for current and charge characteristics of Double Channel (DC) Gallium Nitride High Electron Mobility Transistors (GaN-HEMTs). The model has at its core the self-consistent calculation of the charge densities, for both upper and lower channels, obtained from a solution of the Schrodinger and Poisson equations. Fermi-Dirac (FD) distribution together with 2D density of states is used for mobile carrier statistics in both the channels. Furthermore, drift-diffusion transport is used to compute the channel current using charge densities at channel extremities. Finally, the model is validated against TCAD simulation and experimental data for a DC-GaN-HEMT. The model, by virtue of its fully physics-based nature, precisely captures the charge screening effect in the lower channel without invoking any empirical clamping functions, unlike prior models, and also possesses the feature of being geometrically scalable.

Analysis and Suppression of High Speed Dv/Dt Induced False Turn-on in GaN HEMT Phase-Leg Topology

Gallium nitride high electron mobility transistor (GaN HEMT) is liable to gate false turn-on problem when the gate crosstalk voltage exceeds its threshold voltage in the widely adopted phase-leg topology due to its low threshold voltage and high switching speed. Without considering the gate loop stray inductance, gate internal resistance, nonlinearity of parasitic capacitances and power loop stray parameters, traditional false turn-on analytical method is insufficient to support accurate analysis. And it has been found that GaN HEMT gate-source parasitic capacitance C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> previously assumed constant is otherwise highly nonlinear and has strong impacts on the gate crosstalk voltage. This paper has measured C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> by vector network analyzer and constructed an accurate nonlinear model of C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gs</sub> , based on which an accurate GaN HEMT behavior model is further fulfilled. The accuracy of the proposed behavior model has been verified by large amounts of experiment results. The proposed GaN HEMT model is used to accurately calculate gate crosstalk voltage and switching losses. Besides, false turn-on induced extra loss has been calculated and is adopted as a criterion to evaluate the severity of false turn-on and optimal design method for false turn-on suppression has been detailed further.