GaAs HEMT Research Articles

Electrostatic, linearity and analogue/RF performance analysis of single heterojunction GaAs HEMT

Electrostatic, linearity and analogue/RF performance analysis of single heterojunction GaAs HEMT

Micro-Transfer Printing for Heterogeneous Integration of GaN and GaAs HEMTs

Here, we use the micro-transfer printing technique to demonstrate the device-level heterogeneous integration of two solid-state RF device technologies on the same interposer: GaN and GaAs high-electron-mobility transistors. The devices are released from their growth substrate using an epitaxial sacrificial layer while a thin polymer adhesion layer facilitates a strong bond between the target substrate and the compound semiconductor devices, allowing for post-transfer microfabrication processing. Transmission electron microscopy reveals no voids at the device/interposer interface and a polymer adhesion layer thickness of 5 ± 2 nm. No significant degradation in dc electrical characteristics is observed after device transfer for either device technology. Improvement in thermal performance of GaN devices was demonstrated when transferred to a diamond substrate, even with the thin polymer adhesion layer at the device/interposer interface, illustrating a pathway for enhanced thermal management for GaN and other high-output-power density semiconductor technologies. The ability to combine various solid-state technologies at the device level with high density provides an approach to meet next-generation demands for RF and mixed-signal circuits.

Energy Efficient Enhancement in a 5.8 GHz Batteryless Node Suitable for Backscattering Communications

This work presents a compact batteryless node architecture suitable with the backscattering communication (BackCom) approach. The key functional blocks are demonstrated at 5.8 GHz, making use of commercially available components involving a DC/DC step-up converter, a 3.3 V data generator, and an ASK backscattering modulator based on a single GaAs HEMT in a cold-FET configuration. The node integrates a patch antenna exhibiting a non-50 Ω optimal port impedance; the value is defined by means of a source pull-based optimization technique aimed at maximizing the DC/DC input current supplied by the RF to DC converter. This approach maximizes the node compactness, as well as the wireless power conversion efficiency. A prototype was optimized for the −5 dBm power level at the input of the RF to DC converter. Under this measurement condition, the experimental results showed a 63% increase in the harvesting current, rising from 145 to 237 μA, compared to an identical configuration that used a microstrip matching network coupled with a typical 50-Ω patch antenna. In terms of harvested power, the achieved improvement was from −13.2 dBm to −10.9 dBm. The conversion efficiency in an operative condition improved from 15% to more than 25%. In this condition, the node is capable of charging a 100 μF to the operative voltage in about 27 s, and operating the backscattering for 360 ms with a backscattering modulation frequency of about 10 MHz.

High-Efficiency 28-/39-GHz Hybrid Transceiver Utilizing Si CMOS and GaAs HEMT for 5G NR Millimeter-Wave Mobile Applications

This letter presents the first demonstration of 5G millimeter-wave hybrid front-ends (FEs) for a phased-array transceiver in order to show efficient transmitter performance with low cost and compact area. The configuration of the proposed hybrid FEs is CMOS-based FEs combined with compact GaAs HEMT-based power-cell array to obtain all the benefits of silicon and III-V technology. The architecture and design method of a millimeter-wave transmitter (TX)/receiver (RX) combiner for antenna-port sharing suitable for the proposed hybrid structure is newly introduced. A developed 29-GHz transceiver FE achieves a linear output power of 14.9 dBm with PAE of 28.5% at SC-FDMA 64QAM 100-MHz EVM of −25 dB in TX mode and noise figure (NF) of 5.5 dB in RX mode. Moreover, a developed 38-GHz transceiver FE achieves a linear output power of 12.8 dBm with PAE of 25.2% at SC-FDMA 64QAM 100-MHz EVM of −25 dB in TX mode and NF of 5.5 dB in RX mode.

RF/Linearity figures of merit estimation for GaAs and GaN/SiC-based Nano-HEMTs

The performance of three transistors, a GaAs HEMT, a pHEMT and a GaN/SiC HEMT, was compared. Measurements of the standard device properties have been performed on DC, RF, and nonlinearity characteristics to provide more linear design solutions, which helps the entire system perform properly. The GaAs pHEMT experienced a more comprehensive flat band transconductance profile. Still, the GaN HEMT showed higher power and frequency operation capability in terms of modified Johnson's figure of merit based on the cut-off frequency. In addition, the intermodulation distortion (IMD) components, third-order intercept point, IP3 at low frequencies, i.e., 53 MHz and increasing up to higher frequencies, 3.6 GHz and 7.0 GHz also reported. With the need for a sophisticated semiconductor device with high linearity and excellent power handling capacity, it is essential to look at DC, RF, and nonlinearity comparisons to give more linear design solutions for improving the overall system's performance.

A strategy dedicated to the concise and efficient development of the customized large-signal model for GaAs HEMTs

In this letter, a strategy dedicated to the concise and efficient development of the customized large-signal models for GaAs HEMTs is proposed, which is specialized for MMIC designers. The core concepts of the strategy are a deconstruction of the original thought of model construction and dimension reduction of the objective functions of optimization algorithms. The development of an Angelov-based customized large-signal model following this strategy has been successfully applied to GaAs HEMTs in 70nm process. The results show that it takes less than five minutes to execute such a parameter extraction algorithm with a one-button extraction function and good agreement is achieved between the model simulation and device measurement up to 65GHz.

Measurement‐based analysis of GaAs HEMT technologies: Multilayer D‐H pseudomorphic HEMT versus conventional S‐H HEMT

AbstractThe key objective of this study is to check out the performance of two multilayer processed double‐heterojunction pHEMTs with different gate width as well as one conventional single‐heterojunction HEMT. Different types of investigation have been undertaken by means of on‐wafer DC, small‐signal, and nonlinear two‐tone measurements. The modeling of the DC output characteristics was successfully accomplished using the FET's Curtice model for all of three tested devices. The main figures of merit for microwave and millimeter wave applications have been determined from scattering parameter measurements and then discussed in detail. Furthermore, to attain a better insight of the device behavior, the nonlinear intermodulation distortion behavior has been also studied and compared for the three devices over different bias conditions. A careful analysis of the DC and RF characteristics over a wide range of working conditions is necessary to ensure adequate transistor operation, depending on the given application of interest.

Study of third-order intercepts and nonlinear distortion level for S-H GaAs HEMTs

Third-order intercept (TOI) and nonlinear distortion level (NDL) are studied for two GaAs based single heterostructure HEMTs of different gate width such as (200 μm × 0.5 μm) and (150 μm × 0.5 μm). The TOI being a specific figure of merit is a biasing, input power, frequency-dependent term which is related to the third-order intermodulation distortion (IMD3) component and the study extended from low to high temperatures. The main findings are that the output referenced TOI decreased while the input referenced TOI increased with frequency. Within the measured temperature range, the TOI and NDL change significantly following the behaviour of the IMD3 component. This data would offer assistance in a way that enhances insight of the performance of the GaAs based device working at high frequency and temperature to evaluate the impacts of device nonlinearity on the affectability of the radio and to identify a distortion-free operation.

Integrated impedance bridge for absolute capacitance measurements at cryogenic temperatures and finite magnetic fields.

We developed an impedance bridge that operates at cryogenic temperatures (down to 60 mK) and in perpendicular magnetic fields up to at least 12 T. This is achieved by mounting a GaAs HEMT amplifier perpendicular to a printed circuit board containing the device under test and thereby parallel to the magnetic field. The measured amplitude and phase of the output signal allows for the separation of the total impedance into an absolute capacitance and a resistance. Through a detailed noise characterization, we find that the best resolution is obtained when operating the HEMT amplifier at the highest gain. We obtained a resolution in the absolute capacitance of 6.4 aF/Hz at 77 K on a comb-drive actuator while maintaining a small excitation amplitude of 15 kBT/e. We show the magnetic field functionality of our impedance bridge by measuring the quantum Hall plateaus of a top-gated hBN/graphene/hBN heterostructure at 60 mK with a probe signal of 12.8 kBT/e.

Design of Broadband LNA Using Improved Self-Bias Architecture

A broadband low-noise amplifier (LNA) using 0.13 [Formula: see text]m GaAs HEMT technology for Ku-band applications is presented in this paper. By introducing an improved self-bias architecture, the LNA is achieved with low noise figure (NF) and high power gain. Compared with traditional LNA, self-bias architecture can reduce DC supplies to single one, and the improved architecture proposed here also takes part in source matching to reduce the complexity matching networks for broadband applications. To verify, an LNA operating over 12–18-GHz bandwidth is fabricated. The measurement results, for all the 72 chips on the wafer, and their average values are in great accordance with the simulation results, with 25.5–27.5-dB power gain, 1.1–1.8-dB NF, 15–17.5-dBm output power at [Formula: see text] and with a chip size of 2 mm [Formula: see text] 1.5 mm.

Simulation of the concentration profiles of GaAs LED and HEMT heterostructures

GaAs-based LED and HEMT heterostructures were investigated using numerical simulation of the self-consistent Schrödinger and Poisson equations. The depth distributions of free charge carriers were obtained by simulation and analyzed in detail, then compared to measurements made using the ECV technique.

A solar‐powered 2.4 GHz injection‐locked oscillator for RF amplification

AbstractA 2.4 GHz solar‐powered injection‐locked oscillator (ILO) is developed to boost harvested low‐power radiofrequency (RF) signals for energy harvesting applications. This work proposes a solar‐powered ILO with self‐powering that has a high power efficiency. A solar panel with a regulator circuit directly converts solar power into the electrical power of the ILO. The presented ILO design is based on a single‐ended Clapp oscillator. A direct injection method is used to reduce the power that is consumed by the ILO. The ILO is designed and implemented using Agilent's GaAs HEMT ATF55143. Measurements of the solar‐powered ILO are made and its amplification, or gain, performance is studied; the gain is 18.7 dB. The supply voltage that is applied to the ILO is 1.5 V and the power consumption (PDC) is 1.5 mW.

Automatic large-signal GaAs HEMT modeling for power amplifier design

In this paper, a new nonlinear transistor modeling technique for gallium arsenide high-electron mobility transistor (GaAs HEMT) is proposed. The technique includes an analytical extraction, enhanced by applying nonlinear least squares regression and modified-median method, and a multistage optimization, allowing completely automatic large-signal modeling. Convergence of the technique is proved by a threefold model building procedure followed by the comparison of simulated data like IV-curve and load-pull contours. A 0.15 μm GaAs pHEMT nonlinear model was built and verified with measured IV-curve, multiple bias S-parameters and power characteristics. A good agreement with the measured data proves that the proposed technique enables automatic nonlinear transistor modeling for power MMIC amplifier design.

Planar 0.05–1.1 THz Laminate-Based Transition Designs for Integrating High-Frequency Photodiodes With Rectangular Waveguides

Compact planar laminate-based transitions for integrating high-frequency photodiodes (PDs) with rectangular waveguides (WRs) are presented for the WR15 to WR1 standard waveguide bands, i.e., from 0.05 THz up to 1.1 THz. The transitions couple the optically generated (e.g., via heterodyning) millimeter-wave or terahertz signals from the grounded coplanar waveguide (GCPW) output of the PD chip to the WR. To our knowledge, this is the first scalable integration concept that enables hermetic photodiode packaging up to the terahertz frequency range. For the WR15-WR6 bands, all transitions are designed on ultrathin microfiber reinforced PTFE composites (127-μm Rogers RT/duroid 5880 laminate). For the WR5-WR2.2 and the WR1.5-WR1 bands, liquid crystalline polymer ULTRALAM 3850 laminates are used with a thickness of 50 and 25 μm, respectively. The proposed GCPW-WR transition design is based on a double-slot antenna structure and enables the development of fully hermetic photonic packages, which is required to improve the durability of the PD chip. The transition designs are optimized by systematic EM-wave propagation modeling for achieving a wide operational bandwidth of up to 30% of the respective center frequency for each WR band. The optimized transitions exhibit an average insertion loss of about 1.5 dB and a return loss of about 10 dB for all waveguide bands (WR15-WR1). Based upon the systematic numerical modeling, generic guidelines are developed that allow designing a specific transition for any given waveguide band to 1.1 THz. In addition to the numerical analysis, GCPW-WR12 transitions for E-band (60-90 GHz) operation are fabricated and integrated with InP-based balanced-PD chips and GaAs HEMT MMIC medium power amplifiers in a fully hermetic package. Furthermore, hermetic WR12 coherent photonic mixer (CPX) modules are developed. The packaged WR12-type CPX allows direct optical-to-wireless conversion of optical baseband or IF-band signals, e.g., for radio-over-fiber fronthauling in mobile communications. The WR12-CPX module provides RF output power of up to +15 dB·m at 77.5 GHz.

Design of high‐power W‐band push‐push oscillators using load‐pull technique

AbstractNew design method of push‐push oscillators is proposed using harmonic load‐pull simulation to determine optimum load impedances at both fundamental (f0) and second harmonic frequencies (2f0). It allows high output power at 2f0 while meeting oscillation condition at f0. In addition, the compact self‐biasing source feedback is proposed using coupled line for negative resistance generation. The proposed method is applied to the design of W‐band high power push‐push oscillator using 0.15 μm GaAs pseudo‐morphic high electron mobility transistors (pHEMTs) with typical maximum oscillation frequency (fmax) of 180 GHz. The measurement shows an output power of 2.2 dBm at 92.3 GHz with a phase noise performance of −84 dBc/Hz at 1 MHz offset frequency. This result corresponds to relatively high output power at this frequency compared with reported oscillators using GaAs HEMTs with higher fmax's.

Extrinsic capacitance extraction for GaAs and GaN FETs from low to high temperatures

The main aim of this article is to present an experimental analysis of the thermal influence on the positive derivatives of the real parts of impedance parameters against frequency (PDRZ) for microwave GaN and GaAs based HEMTs. The PDRZ effect is investigated with respect to temperature by both heating and cooling the studied devices. The main findings are that both devices are affected by the PDRZ effect, although with different severity and onset frequency. Due to the extrinsic resistances response with temperature, the real parts of impedance parameters shift towards higher values, especially for the GaAs HEMT. By de-embedding appropriate values of the extrinsic capacitances, the PDRZ effect can be neutralized in both devices. As the extrinsic capacitances are thermally unresponsive, roughly the same values of the extrinsic capacitances are achieved for all the studied temperatures.

Specific Features of the Electrochemical Capacitance–Voltage Profiling of GaAs LED and pHEMT Structures with Quantum-Confined Regions

GaAs light-emitting (LED) and HEMT structures with δ-doped regions, InGaAs/GaAs quantum wells, and surface layers of InAs/GaAs quantum dots were studied by means of the electrochemical capacitance- voltage profiling technique. The concentration depth profiles of free charge carriers were obtained. Charges accumulated in quantum wells and quantum dots, as well as the doping levels of the emitter and δ layers were determined. The band structure and free carrier density distribution over the depth of the samples with different quantum well geometry were simulated. The specific features of electrochemical capacitance- voltage profiling in different heterostructure types are analyzed. A method of integration of capacitance- voltage curves at each etching stage was suggested. This method provides the efficient separation of responses from closely located layers, particularly the quantum well and δ layer.

Device behaviour and zero temperature coefficients analysis for microwave GaAs HEMT

Detailed analysis of device behaviour on the zero-temperature coefficient (ZTC) points for microwave GaAs based high-electron mobility transistor is presented by means of on-wafer measurements over the temperatures between −40 and 150 °C. This zero temperature coefficient points found not only in the transfer and transconductance curve but also in intrinsic transconductance gmo, output conductance gds, small signal gain S21, and minimum noise figure NFmin also exhibits ZTC. It is found that the zero temperature coefficients points are impacted by both threshold voltage and drain bias. The transfer current base, ZTCIds moved from 0.1 V to −0.2 V of Vgs trace and transconductance based, ZTCgm moved from −0.3 V to −0.6 V of Vgs trace with the drain bias, Vds varies from 1 V to 5 V. The behaviour of some intrinsic equivalent circuit parameters along with cut-off frequency, ft at both ZTC bias points opens some crucial insight and opportunities in microwave device design for low and high temperature applications.

Nonlinear distortion analysis for single heterojunction GaAs HEMT with frequency and temperature

Nonlinearity analysis using two-tone intermodulation distortion (IMD) technique for 0.5 μm gate-length AlGaAs/GaAs based high electron mobility transistor have been investigated based on biasing conditions, input power, frequency and temperature. The outcomes indicate a significant modification on the output IMD power and as well as the minimum distortion level. The input IMD power effects the output current and subsequently the threshold voltage reduces, resulting to an increment in the output IMD power. Both frequency and temperature reduces the magnitude of the output IMDs. In addition, the threshold voltage response with temperature alters the notch point of the nonlinear output IMD’s accordingly. The aforementioned investigation will help the circuit designers to evaluate the best biasing option in terms of minimum distortion, maximum gain for future design optimizations.

Varactor‐tunable dual‐band filtering low‐noise amplifier

AbstractDesign and development of a tunable dual‐band filtering LNA has been presented in this paper. The center frequency of the lower band is continuously tuning with applied dc voltages. The center frequency of lower band has a tuning range of 2.0–2.5 GHz; while that of upper band is fixed at 5 GHz. Power consumption of our circuit is 28 mW. Overall size of proposed device is 0.96λg × 0.34λg, where λg is the guided wavelength at lower frequency. One ATF36163 GaAs HEMT is used as the active device in our circuit. Measured per stage gain of lower band is varying from 8 to 1.6 dB; while that of upper band is 5.4 dB. Measured noise figure of lower band is 2.4–3.4 dB; while that of upper band is 2.5 dB. Proposed filtering LNA has improved selectivity and spurious harmonic suppression with measured stopband attenuation of 45 dB. To author's knowledge, the investigation of tunable multiband and multifunctional device for highly improving the level of integration of the multiband RF front‐end design is reported for the first time.