GaAs High Electron Mobility Transistor Research Articles

Third generation semiconductor device research: Optimizing CMOS and HEMT designs

The third-generation semiconductor device known as High Electron Mobility Transistors (HEMT) has found extensive applications in high-frequency and high-speed electronic systems. Its widespread usage in critical technologies such as radio telescopes, satellite broadcast receivers, and cellular base stations has established HEMT as a foundational technology underpinning our information and communication society. This paper provides an in-depth exploration of these semiconductor advancements. Firstly, the paper utilizes the CMOS inverter as a representative example to elucidate the fundamental structure of Complementary Metal-Oxide-Semiconductor (CMOS) technology. Additionally, it employs Gallium Arsenide (GaAs) HEMT as an illustrative instance to expound upon the architecture of HEMT devices. Furthermore, the paper delves into the optimization of CMOS technology, focusing on topics such as Multi-Threshold CMOS and the impact of the Width/Length (W/L) ratio. These discussions shed light on ways to enhance the performance of CMOS-based components. Additionally, the paper explores strategies to optimize HEMT devices, including the introduction of carbon doping and the application of the Grey-Wolf optimization technique. These approaches are critical in achieving higher efficiency and performance in HEMT-based applications.

Analysis & development of automated system for on-wafer channel thermal measurement of RF power devices using ordinary lab instruments

Accurate and precise measurement of channel temperature for RF devices and especially for high power density devices such as MESFETs and GaAs High Electron Mobility Transistors (HEMTs) is essential for understanding the physics behind device degradation. In high power density devices, self-heating effects (SHEs) and channel to base plate temperature gradients are very high. This paper proposes an automated experimental setup using ordinary lab instruments for the measurement of channel temperature of MESFETs and HEMTs in terms of thermal resistance (θth) and thermal capacitance (Cth). The automated experimental setups utilize ordinary lab equipment instead of using specialized high-end tools. With ambient temperature, DC bias conditions, and RF power levels, channel temperature is calculated using θth and Cth parameters. The proposed technique is applied on three different HEMTs and the results were similar for all of them which reflect accuracy of the technique.

A Time Delay Neural Network Based Technique for Nonlinear Microwave Device Modeling.

This paper presents a nonlinear microwave device modeling technique that is based on time delay neural network (TDNN). The proposed technique can accurately model the nonlinear microwave devices when compared to static neural network modeling method. A new formulation is developed to allow for the proposed TDNN model to be trained with DC, small-signal, and large signal data, which can enhance the generalization of the device model. An algorithm is formulated to train the proposed TDNN model efficiently. This proposed technique is verified by GaAs metal-semiconductor-field-effect transistor (MESFET), and GaAs high-electron mobility transistor (HEMT) examples. These two examples demonstrate that the proposed TDNN is an efficient and valid approach for modeling various types of nonlinear microwave devices.

Guest Editorial for the special issue on devices and circuits for millimeter‐wave and THz applications

Guest Editorial for the special issue on devices and circuits for millimeter‐wave and THz applications

The influence of MBE and device structure on the electrical properties of GaAs HEMT biosensors * * Project supported by the National Key Research and Development Program of China (No. 2017YFB0405400), the Open Research Fund Program of the State Key Laboratory of Virology of China (No. 2017IOV002), the National Natural Science Foundation of China (Nos. 61274049, 61404130, 61574140), and the

High electron mobility transistors (HEMT) have the potential to be used as high-sensitivity and real-time biosensors. HEMT biosensors have great market prospects. For the application of HEMT biosensors, the electric properties consistency of the inter-chip performance have an important influence on the stability and repeatability of the detection. In this research, we fabricated GaAs/AlGaAs HEMT biosensors of different epitaxial structures and device structures to study the electric properties consistency. We study the relationship between channel size and consistency. We investigated the distribution of device current with location on 2 inch GaAs wafer. Based on the studies, the optimal device of a GaAs HEMT biosensor is an A-type epitaxial structure, and a U-type device structure, L = 40 μm, W = 200 μm.

COMPARATIVE ANALYSIS OF DIFFERENT CAD METHODS FOR EXTRACTION OF THE HEMT NOISE WAVE MODEL PARAMETERS

The noise wave model has appeared as a very appropriate model for the purpose of transistor noise modeling at microwave frequencies. The transistor noise wave model parameters are usually extracted from the measured transistor noise parameters by using time-consuming optimization procedures in microwave circuit simulators. Therefore, three different Computer-Aided Design methods that enable more efficient automatic determination of these parameters in the case of high electron-mobility transistors were developed. All of these extraction methods are based on different noise de-embedding procedures, which are described in detail within this paper. In order to validate the presented extraction methods, they were applied for the noise modeling of a specific GaAs high electron-mobility transistor. Finally, the obtained results were used for the comparative analysis of the presented extraction approaches in terms of accuracy, complexity and effectiveness.

A Wiener-Type Dynamic Neural Network Approach to the Modeling of Nonlinear Microwave Devices

A new Wiener-type dynamic neural network (DNN) approach for nonlinear device modeling is proposed in this paper. The proposed analytical formulation of Wiener-type DNN structure consists of a cascade of a simplified linear dynamic part and a nonlinear static part. The simplified linear dynamic equations are obtained by vector fitting enhancing the efficiency of the model. A new formulation and new sensitivity analysis technique is derived to train the proposed Wiener-type DNN with dc, small- and large-signal data. A new gradient-based training algorithm is also formulated to speed up the training of proposed Wiener-type DNN model. The proposed Wiener-type DNN model can be trained to be accurate relative to device data. Furthermore, the proposed Wiener-type DNN provides enhanced convergence properties over existing neural network approaches such as time delay neural network (TDNN) and TDNN with extrapolation. Application examples on modeling GaAs metal-semiconductor-field-effect transistor, GaAs high-electron mobility transistor (HEMT), and a real <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 \times 50$ </tex-math></inline-formula> gatewidth GaAs pseudomorphic HEMT are presented. The use of Wiener-type DNN model in harmonic balance simulations demonstrates that the Wiener-type DNN is a robust method for developing models for different types of microwave devices. These models could be implemented into circuit simulators conveniently.

Damage effect and mechanism of the GaAs high electron mobility transistor induced by high power microwave**Project supported by the National Basic Research Program of China (Grant No. 2014CB339900) and the Open Fund of Key Laboratory of Complex Electromagnetic Environment Science and Technology, China Academy of Engineering Physics (Grant No. 2015-0214.XY.K).

In this paper, we present the damage effect and mechanism of high power microwave (HPM) on AlGaAs/GaAs pseudomorphic high-electron-mobility transistor (pHEMT) of low-noise amplifier (LNA). A detailed investigation is carried out by simulation and experiment study. A two-dimensional electro-thermal model of the typical GaAs pHEMT induced by HPM is established in this paper. The simulation result reveals that avalanche breakdown, intrinsic excitation, and thermal breakdown all contribute to damage process. Heat accumulation occurs during the positive half cycle and the cylinder under the gate near the source side is most susceptible to burn-out. Experiment is carried out by injecting high power microwave into GaAs pHEMT LNA samples. It is found that the damage to LNA is because of the burn-out at first stage pHEMT. The interiors of the damaged samples are observed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). Experimental results accord well with the simulation of our model.

Failure Analysis on Damaged GaAs HEMT MMIC Caused by Microwave Pulse

Failure examination is carried out by a scanning electron microscope on gallium arsenide (GaAs) high electron mobility transistor (HEMT) monolithic microwave integrated circuit damaged with microwave pulses. The examination results show that there are four types of defects in ten damaged chips. Among the previous types, one type of defect occurred in most damaged chips was examined, namely the planar spiral inductor between the output terminal of the last-stage HEMT and dc power supply is burned out. Specific to this type of defect, combining with the conductor loss theory and heat formula, the mechanism of heating and melting exerted on the planar spiral inductor of the chip under the action of microwave pulses is analyzed in this paper. The input power required for reaching Au and Cu microstrip melting point is computed.

Influence of InGaP and AlGaAs Schottky Layers on ESD Robustness in GaAs pHEMTs

GaAs high-electron-mobility transistors (HEMTs) have been widely used for radio-frequency (RF) applications due to the excellent material properties. One of the essential elements of the HEMTs is the gate Schottky barrier layer. InGaP has been proposed and proven as a better Schottky barrier material for the RF performance of the GaAs HEMTs. This letter investigates the influence of the GaAs HEMTs with two different Schottky layers, which are InGaP and AlGaAs on device transient characteristics under electrostatic discharge (ESD) stress. Although InGaP presents significant advantages on improving RF performance of GaAs HEMTs, it shows inferiority in ESD robustness.

An extraction technique for small signal intrinsic parameters of HEMTs based on artificial neural networks

This paper presents a fast and accurate procedure for extraction of small signal intrinsic parameters of AlGaAs/GaAs high electron mobility transistors (HEMTs) using artificial neural network (ANN) techniques. The extraction procedure has been done in a wide range of frequencies and biases at various temperatures. Intrinsic parameters of HEMT are acquired using its values of common-source S-parameters. Two different ANN structures have been constructed in this work to extract the parameters, multi layer perceptron (MLP) and radial basis function (RBF) neural networks. These two kinds of ANNs are compared to each other in terms of accuracy, speed and memory usage. To validate the capability of the proposed method in small signal modeling of GaAs HEMTs, data and modeled values of S-parameters of a 200μm gate width 0.25μm GaAs HEMT are compared to each other and very good agreement between them is achieved up to 30GHz. The effect of bias, temperature and frequency conditions on the extracted parameters of HEMT has been investigated, and the obtained results match the theoretical expectations. The proposed model can be inserted to computer-aided design (CAD) tools in order to have an accurate and fast design, simulation and optimization of microwave circuits including GaAs HEMTs.

GaAs HEMT as sensitive strain gauge

A strong piezoresistive effect of GaAs micro-structure which is based on high electron mobility transistor (HEMT) is reported in this paper. The GaAs HEMT is embedded in the root of the cantilever as the sensitive element in order to detect the deformation. The strain is simulated with the ANSYS software, and the maximum gauge factor is about 26,350, which is nearly a hundred times larger than that of piezoresistive silicon. The high gauge factor is not only due to the option of voltage bias, but also the combination of the piezoresistive and piezoelectric effect. The obtained results demonstrate that GaAs micro-structure based on HEMT can be suitable for high sensitive stress/pressure sensors.

Temperature-Dependent Microwave Noise Characteristics in ALD $\hbox{Al}_{2}\hbox{O}_{3}$/AlGaN/GaN MISHEMTs on Silicon Substrate

Temperature-dependent microwave noise characteristics are presented in an atomic-layer-deposited /AlGaN/GaN metal-insulator-semiconductor high-electron mobility transistor (HEMT) (MISHEMT) on a Si substrate over a wide temperature range from -40 to 200 C. Typical noise parameters, including minimum noise figure , noise equivalent resistance , and associate gain , are measured over the whole temperature range. The conventional Schottky-gate HEMT with the same epistructure is also compared. The temperature dependences of and for the MISHEMT are found to be similar to those for the conventional HEMT, respectively, whereas less temperature dependence of is found in the GaN MISHEMT. The degradation rate of the noise performance of MISHEMT is found to be comparable to that of the other reported GaN HEMTs on SiC and sapphire substrates and also comparable to that of GaAs HEMTs.

Design and Analysis of a DC–43.5-GHz Fully Integrated Distributed Amplifier Using GaAs HEMT–HBT Cascode Gain Stage

Design and analysis of a dc-43.5-GHz fully integrated distributed amplifier (DA) using a GaAs high electron-mobility transistor (HEMT) heterojunction bipolar transistor (HBT) cascode gain stage is presented in this paper. The proposed DA is fabricated in a stacked 2- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu{\hbox {m}}$</tex></formula> InGaP/GaAs HBT, 0.5- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu{\hbox {m}}$</tex></formula> AlGaAs/GaAs enhancement- and depletion-mode HEMT monolithic microwave integrated circuit technology. A modified <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$m$</tex> </formula> -derived network and an HEMT–HBT cascode amplifier with inductive peaking technique are investigated to enhance the bandwidth of the DA. The bias networks of the DA are fully integrated in a single chip without off-chip bias-T or bias components. The measured average small-signal gain is 8.5 dB. The measured minimum noise figure is 4.2 dB. The measured maximum output 1-dB compression point <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$({ P}_{1\ {\rm {dB}}})$</tex></formula> and the maximum output third-order intercept point are 8 and 18 dBm, respectively. Moreover, the DA is successfully evaluated with an eye diagram measurement, and demonstrates good transmission quality.

HIGH MAGNETIC FIELD IN THz PLASMA WAVE DETECTION BY HIGH ELECTRON MOBILITY TRANSISTORS

The role of gated and ungated two dimensional (2D) electron plasma in THz detection by high electron mobility transistors (HEMTs) was investigated. THz response of GaAs / AlGaAs and GaN / AlGaN HEMTs was measured at 4.4K in quantizing magnetic fields with a simultaneous modulation of the gate voltage UGS. This allowed us to measure both the detection signal, S, and its derivative d S/ d UGS. Shubnikov - de-Haas oscillations (SdHO) of both S and d S/ d UGS were observed. A comparison of SdHO observed in detection and magnetoresistance measurements allows us to associate unambiguously SdHO in S and d S/ d UGS with the ungated and gated parts of the transistor channel, respectively. This allows us to conclude that the entire channel takes part in the detection process. Additionally, in the case of GaAlAs / GaAs HEMTs, a structure related to the cyclotron resonance transition was observed.

Scanning electron and laser beams induced current (SELBIC) method for observing failures in GaAs high electron mobility transistors

The electrical imaging observation of failures in GaAs high electron mobility transistors (HEMTs) is performed using scanning electron and laser beams induced current (SELBIC) method. An electron beam and infrared (IR) laser beam with a wavelength of 1064 nm irradiate coaxially from each side of a HEMT sample. When HEMT sample#1 and #2 are scanned from the back surface using a laser beam, a high contrast spot in the current image of sample#1 was observed between the gate and source regions. Since the I – V characteristic between the gate and source shows an increase in leakage current, the high contrast spot in the current image is suggested to be an electrically active failure. The current image is compared with the image under electron beam irradiation. It is ascertained by a cross sectioning technique with focused ion beam (FIB). The current spot is due to a crack causing a local short circuit in an insulating layer.

GaAs HEMT Reliability and Degradation Mechanisms after Long Term Stress Testing

AbstractGaAs based metamorphic and pseudomorphic high electron mobility transistors (HEMTs) under DC and thermal stress were studied. InAlAs/InGaAs MHEMTs grown on GaAs substrates were stressed at a drain voltage bias of 2.7V for 36 hours as well as thermally stressed at 250°C for 36 hours. Under both stress conditions, the drain current density decreased about 12.5%. The gate current, however, increased more after the thermal storage as opposed to DC bias. Reaction of the Ohmic contact with the underlying semiconductor was the main cause of degradation after thermal stressing. Transmission electron microscopy verified that gate sinking occurred in devices that underwent DC bias stressing. InGaAs pHEMTs that received a 1000 hour lifetime stress test from a commercial vendor showed similar degradation as virgin devices when stressed under DC bias for 24 hours. Virgin devices that were thermally stressed while undergoing DC bias showed minimal degradation up to 120°C, but exhibited catastrophic failure at 140°C.

Electron heating and huge positive magnetoresistance in an AlGaAs∕GaAs high electron mobility transistor structure at high temperatures

We have performed magnetoresistivity measurements ρxx(B) on an AlGaAs∕GaAs high electron mobility transistor (HEMT) structure at high temperatures T. The observed positive magnetoresistance (MR) in the HEMT structure can be greatly enhanced simply by increasing the driving current. At T=80K and B=6T, the MR value can be increased from ∼150% to 4000%, almost a 30-fold increase when a large current of 40μA is applied. Such results are due to electron heating effects and our data lay the foundation for practical magnetic device applications which can be readily combined with high-speed electronics, high-frequency amplifiers, and radar using the mature GaAs-based HEMT technology.

Huge positive magnetoresistance in a gated AlGaAs∕GaAs high electron mobility transistor structure at high temperatures

Magnetoresistivity measurements on a gated AlGaAs∕GaAs high electron mobility transistor (HEMT) structure were performed at high temperatures T. By changing the applied gate voltage Vg, we can investigate the observed huge positive magnetoresistance (PMR) at different effective disorder and density inhomogeneity within the same HEMT structure. The observed PMR value increases with increasing disorder in the depletion mode (Vg⩽0). Moreover, the PMR value is not limited by the quality of the HEMT structure at T=80K. Such results pave the way for low-cost, high-throughput GaAs-based HEMT fabrication for future magnetic sensing and recording devices fully compatible with the mature HEMT technology.

35-nm Zigzag T-Gate $\hbox{In}_{0.52}\hbox{Al}_{0.48} \hbox{As/In}_{0.53}\hbox{Ga}_{0.47}\hbox{As}$ Metamorphic GaAs HEMTs With an Ultrahigh $f_{\max}$ of 520 GHz

Metamorphic GaAs high electron mobility transistors (mHEMTs) with the highest- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> reported to date are presented here. The 35-nm zigzag T-gate In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.52</sub> Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.48</sub> As/In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.53</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.47</sub> As metamorphic GaAs HEMTs show <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> of 520 GHz, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> of 440 GHz, and maximum transconductance ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> ) of 1100 mS/mm at a drain current of 333 mA/mm. The combinations of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> and <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> are the highest data yet reported for mHEMTs. These devices are promising candidates for aggressively scaled sub-35-nm T-gate mHEMTs.