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The purpose of this paper is to report on the stabilization network optimization of internally matched GaN high electron mobility transistors (HEMTs).

The effects of the two stabilization networks on the characteristics of the device are discussed, such as the stability, power gain and output power.

With the optimized stabilization network, the internally matched GaN HEMTs with 16‐mm gate width exhibited good stability and delivers a 46 dBm output power with 6.1 dB power gain under the continuous wave condition at 8 GHz. By using the optimized stabilization network, the package process of the large‐scale microwave power device of GaN HEMTs can be simplified.

This paper provides useful information for the internally matched GaN HEMTs.

A two‐dimensional numerical computer simulation based on the analysis of the first three moments of the Boltzmann equation, known as the energy‐transport model, has been used to study various two‐dimensional effects on the performance of AlGaAs/GaAs heterostructure field‐effect transistor. The results are presented for half‐micron gate length. The calculation reveals significant electron current contribution coming from the AlGaAs region between the source and gate, contributing to the reduction of access resistance. As the electrons acquire large energies near the drain side edge of the gate, real‐space transfer to the AlGaAs region from the “two‐dimensional” electron gas channel occurs. However, at the drain end, the electron current is confined at the GaAs side of the heterointerface. The result shows insignificant current contribution from regions of depth greater than 0.048 µm into the undoped GaAs bulk. At room temperature, the results indicate transconductance, current gain cutoff frequency and power density about twice that which are calculated for “equivalent” GaAs MESFET, of identical structure and doping level as the heavily‐doped AlGaAs region. These results suggest that HEMT devices have the potential for providing significant sources of power at millimeter‐wave frequencies.

To design and optimize the traditional aluminum gallium nitride/gallium nitride high electron mobility transistor (HEMT) device in achieving improved performance and current handling capability using the Synopsys’ Sentaurus TCAD tool.

Varying material and physical considerations, specifically investigating the effects of graded barriers, spacer interlayer, material selection for the channel, as well as study of the effects in the physical dimensions of the HEMT, have been extensively carried out.

Critical figure-of-merits, specifically the DC characteristics, 2DEG concentrations and mobility of the heterostructure device, have been evaluated. Significant observations include enhancement of maximum current density by 63 per cent, whereas the electron concentration was found to propagate by 1,020 cm⁻³ in the channel.

This work aims to provide tactical optimization to traditional heterostructure field effect transistors, rendering its application as power amplifiers, Monolithic Microwave Integrated Circuit (MMICs) and Radar, which requires low noise performance and very high radio frequency design operations.

Analysis in covering the breadth and complexity of heterostructure devices has been carefully executed through extensive TCAD modeling, and the end structure obtained has been optimized to provide best performance.

The purpose of this paper is to report upon high power, internally matched GaN high electron mobility transistors (HEMTs) at Ku band with 1.5 GHz bandwidth, which employ a simple and cost‐effective lossless compensated matching technique.

Two 4 mm gate periphery GaN HEMTs are parallel combined and internally matched with multi‐section reactive impedance transformers at the input and output networks. The output matching network is designed at the upper frequency of the design band for a flat power of the circuit, while the input matching network is designed at the upper frequency for a flat gain.

With the reactively compensated matching technique, the internally matched GaN HEMTs exhibit a flat saturated output power of 43.2+0.7 dBm and an average power added efficiency of 15 per cent over 12 to 13.5 GHz.

This paper provides useful information for the internally matched GaN HEMTs.

This paper aims to investigate the sintering and solid liquid interdiffusion bonding (SLID) techniques to attach AlGaN/GaN-on-Si chips to direct bond copper (DBC) substrate. The influence of metal layers deposited on the backside of AlGaN/GaN-on-Si dies on the assembly process is also investigated.

The authors assumed the value of the shear strength to be a basic parameter for evaluation of mechanical properties. Additionally, the surface condition after shearing was assessed by SEM photographs and the shear surface was studied by X-ray diffraction method. The SLID requires Sn-plated DBC substrate and can be carried out at temperature slightly higher than 250°C and pressure reduced to 4 MPa, while the sintering requires process temperature of 350°C and the pressure at least 7.5 MPa.

Ag-, Au-backside covered high electron mobility transistor (HEMT) chips can be assembled on Sn-plated DBC substrates by SLID technology. In case of sintering technology, Cu- or Ag-backside covered HEMT chips can be assembled on Ag- or Ni/Au-plated DBC substrates. The SLID process can be realized at lower temperature and decreased pressure than sintering process.

For SLID technology, the adhesion between Cu-backside covered HEMT die and DBC with Sn layer loses its operational properties after short-term ageing in air at temperature of 300°C.

In the SLID process, Sn-Cu and Sn-Ag intermetallic compounds and alloys are responsible for creation of the joint between Sn-plated DBC and micropowder Ag layer, while the sintered joint between the chip and Ag-based micropowder is formed in diffusion process.

The purpose of this paper is to study conducted electromagnetic interference (EMI) of the high-low voltage DC/DC converter based on GaN high-electron-mobility transistors (HEMTs) in electric vehicle, and design EMI filters to suppress the conducted EMI.

The conducted EMI propagation model is established through simulation and analysis studying the influences of parasitic parameters, operation mode, output power and near-field capacitive coupling effects on conducted EMI of the DC/DC converter and comparing the suppression effects of EMI filters with different topologies to select the best EMI filter.

It is shown that parasitic parameters, operation mode, output power and near-field capacitive coupling effects can affect the conducted EMI of the DC/DC converter, and EMI filters of the CLC topology can effectively suppress the conducted EMI below the limit of CISPR 25.

Analysis of conducted EMI and design of EMI filters greatly facilitate further explorations and studies on EMI problems of the high-low voltage DC/DC converter based on GaN HEMTs.

This study aims to present two stage pseudomorphic high electron mobility transistor-based low noise amplifier (LNA) designed using low temperature co-fire ceramic (LTCC) technique for ultra-high frequency (UHF) band. The LNA operates in the frequency range of (400∼500) MHz which is suitable for wireless communication applications.

This LNA uses resistive capacitive (RC) feedback in the first stage to have wide bandwidth and interstage network for gain enhancement. By using external RC feedback, stability is improved and noise matching in the input stage is isolated by decoupling inductor. The excellent performance parameters including gain, noise figure (NF), wideband and linearity are attained without affecting the power consumption, compactness and cost of the proposed design.

Simulation is carried out using advanced design software and the result shows that gain of 33.7 dB, NF 0.416 dB and 1 dB compression point (P_1dB) of 18.59 dBm are achieved with a supply voltage of 2.5 V. The return loss of input and output are −19.3 dB and −10.5 dB, respectively. From the above aforementioned parameters, it is confirmed that the proposed LNA is a promising candidate for receivers where high gain and very low NF are always demandable with good linearity for applications operating in the UHF band.

The innovation of the proposed LNA is that the concurrent attainment of high gain, low NF, wideband, optimum input matching, good stability by RC feedback and interstage network using LTCC technique to achieve robustness, low cost and compactness to prove the applicability of design for wireless applications.

The effect of doping the quantum well (QW) on the distribution of two dimensional electron gas (2DEG) in high electron mobility transistors (HEMT) is discussed. In con‐ventional HEMTs the QW is unintentionally doped to utilize the higher mobility of the QW material. The overlap between the carrier and the dopant distribution may be minimized by selectively doping the QW.

Noise parameters of high electron mobility transistors (HEMT) at microwave frequencies are a subject of active research since the knowledge of their performance is of key importance for the use of these devices for designing low‐noise amplifiers. Employs a simple noise model to derive the analytical expressions for the device noise parameters F₀, Γ₀ and N in terms of the electrical elements associated with the basic equivalent circuit of an HEMT. Analyses such expressions to establish some fundamental relationships, as well as the expected noise performance of the device when the parasitic elements representing package effects are included.

This 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.

A 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.

In 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.

Each 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.