GaAs Metamorphic High Electron Mobility Research Articles

60 GHz Low-Noise Amplifier for Detection Systems

This paper presents a 60 GHz low-noise amplifier (LNA) to improve detection systems performance. The considered system is based on impulse radar technology. The LNA is designed in GaAs metamorphic High Electron Mobility Transistor (m-HEMT) technology. Three stages common source transistors are used with inductive degeneration for a good tradeoff between gain and noise. The post-layout simulation results show a noise factor of 2.06 dB and a gain of 14.5 dB at 60.2 GHz, for a power consumption of 13.5 mW. The simulated nonlinear characteristics show an IP 1dB (Input 1 dB compression Point) of -10 dBm and an IIP3 (Input third-order Intercept Point) of -4.4 dBm. The LNA occupies an area of 1.56 × 1.29 mm2.

GaAs metamorphic high electron mobility transistors for future deep space-biomedical-millitary and communication system applications: A review

Following the introduction of metamorphic high electron mobility transistors (MHEMTs) 30 years back, there has been a rapid growth in their use in advanced MMIC (monolithic microwave integrated circuit) and TMIC (Terahertz monolithic integrated circuit) applications in sub-millimetre wave (S-MMW) and terahertz (THz) frequency regime. Undoubtedly, they are capable of making a great impact in applications such as deep space, cryogenic, biomedical instrumentation, military, high speed communication networks etc, in the years to come. This review article not only studies the progress of depletion mode (D-Mode), enhancement mode (E-Mode) type MHEMTs in the last 30 years, extensively but also critically and systematically analyzes the fabrication challenges, reliability issues and their use in cryogenic fields. Yet another highlight is that the work also carefully examines the utility of MHEMTs in deep space, biomedical, scientific, military, communication areas and so forth.

A broadband low noise amplifier in 70nm GaAs MHEMT process

In this paper, a broadband low noise amplifier (LNA) is presented with 70nm GaAs metamorphic high electron mobility transistor (MHEMT) process. The feedback and input/output impedance match techniques for broadband amplifier are presented. The stability, noise figure, gain flatness, and S-parameter performance of this LNA are analyzed and discussed. The small signal gain of the LNA is 20dB±0.2dB and noise figure of 0.86dB~1.35dB among operating from almost DC to 15GHz. This LNA exhibits reflection below -10dB, power dissipation of 70mW and chip area of 1.0mm*0.6mm. This LNA finds its application in many wideband systems.

A $G$ -Band Broadband Balanced Power Amplifier Module Based on Cascode mHEMTs

The first full $G$ -band power amplifier module demonstrated in GaAs metamorphic high electron mobility transistor (mHEMT) technology has been developed for use as a driver amplifier in instrumentation. The circuit integrated in this module uses a compact balanced cascode topology and is based on a 35-nm mHEMT technology in a grounded coplanar waveguide environment. High compactness is achieved due to the use of a small ground-to-ground spacing of $14~\mu {\mathrm{ m}}$ and an advanced process with three metallization layers. The millimeter-wave integrated circuit exhibits a linear gain higher than 15.3 dB and return losses better than 10 dB from 118 to 236 GHz, which represents an ultrabroad relative bandwidth (RBW) of 67%. A peak output power of 10 dBm is achieved at 200 GHz. The WR-5 module uses broadband transitions, which show insertion losses of less than 1.5 dB. It demonstrates a small-signal gain that exceeds 13.4 dB in the whole $G$ -band (RBW ≥ 54%). Large-signal characterization exhibits power levels higher than 3.6 dBm from 130 to 210 GHz (RBW = 47%). This module achieves the highest bandwidth in $G$ -band and the highest output power when comparing it with modules based on similar technologies.

Investigation of DC-RF and breakdown behaviour in Lg = 20 nm novel asymmetric GaAs MHEMTs for future submillimetre wave applications

In this work, we systematically investigated the DC-RF and breakdown voltage characteristics of Lg = 20 nm novel asymmetric GaAs metamorphic high electron mobility transistor (MHEMT) using Sentaurus-TCAD tool. The highlights of the novel asymmetric GaAs MHEMT are the cavity in the asymmetric Γ-gate region, n+-type In0.52Al0.48As/In0.53Ga0.47As/In0.75Ga0.25As cap layers and n+-type In0.52Ga0.48As vertical source/drain (S/D) regions. The influence of asymmetric gate recess width on DC-RF and ON and OFF-state breakdown voltage characteristics of the novel asymmetric GaAs MHEMT has been systematically investigated using hydrodynamic (HD) charge transport model. The physical models such as impact ionization model, high electric field electron mobility model, Shockley-Read-Hall and recombination models and density gradient model are also included during room temperature Sentaurus-TCAD simulation in order to accurately obtain the DC-RF and breakdown performance parameters. The 20 nm gate length novel asymmetric GaAs MHEMT obtained a maximum transconductance (gm_max) and drain current IDS_max of 3350 mS/mm and 1230 mA/mm respectively. The transit frequiencies fT and fmax obtained by the proposed 20 nm gate length GaAs MHEMT are 643 GHz and 1230 GHz respectively. The 20 nm gate length novel asymmetric GaAs MHEMT also exhibited an ON-state (BVON) and OFF-state (BVOFF) breakdown voltages of 3.1 V and 7.2 V respectively. To the best knowledge of authors, this is the record combination of DC–RF and breakdown performance parameter values obtained for GaAs MHEMT which makes them highly suitable for next generation high power high speed applications.

Accuracy improvement of small‐signal model minimising parameter sensitivity based on de‐embedded sub‐model method at W‐band

A highly reliable small-signal parameter extraction method for parasitic elements of the 0.1-µm GaAs metamorphic high electron mobility transistors is presented. De-embedding scheme for the coplanar waveguide (CPW) feeding structure is utilised in this method in a frequency range of 0.5–110 GHz with an enhancement approach to the correction of source inductance parameter sensitivity derived from oscillating measurements. The parasitic extrinsic capacitances are determined by modelling an ∏ equivalent circuit including the interaction between the sub-model and the CPW feedings. From this method, the authors achieved the most accurate parameter prediction with an effective fitting error of 10.83% among the small-signal models reported to date.

Monolithic Ka to Ku-Band All Balanced Sub-Harmonic Resistive MHEMT Mixer for Satellite Transponder

This letter presents the design and measured performance of a novel Ka to Ku-band all balanced sub-harmonic resistive mixer monolithic microwave integrated circuit (MMIC). A new topology using 0.13 $\mu{\rm m}$ GaAs metamorphic high-electron mobility transistor (mHEMT) based mixing quad is implemented to reject mixing product spurious signals involving even order of radio frequency (RF). Measured performance shows more than 50 dB of isolation for the second harmonic of the local oscillator (LO) signal at the RF and intermediate frequency (IF) ports, which is better than earlier reported data for field-effect transistor (FET) based sub-harmonic resistive mixers to the best of the authors' knowledge. In-band mixing product spurious of ( $-$ 2RF, $+$ 8LO) is found 70 dBc down with reference to the desired IF level for $-$ 10 dBm of RF input power. Effects of coupling on the mixer performance are also discussed through various electromagnetic simulations and measured results. Mixer exhibits conversion loss of about 9.5 dB.

An Active 60-90 GHz Single Pole Double Throw Switch MMIC

This paper introduces an active millimeter-wave switch in a GaAs metamorphic high electron mobility transistor (mHEMT) technology. The active switch exhibits broadband performance (60 to 90 GHz, 40%), a gain of 10 dB with flat frequency response and average noise figure of 2.8 dB. The unilateral receiver topology is dedicated to radiometry applications. The design combines two input-matched low noise amplifiers with an output capacitance compensation network. The switch consumes 28 mW.

Millimeter-Wave Small-Signal Model Using A Coplanar Waveguide De-Embedded Sub-Model for HEMT

We propose in this study an approach to highly reliable extraction method for parasitic elements of the 0.1 μm GaAs metamorphic high electron mobility transistors. This method utilizes the de-embedding scheme for the coplanar waveguide (CPW) feeding structure by considering the distributed extrinsic parasitic elements in our small-signal model. The parasitic extrinsic capacitances are determined by modeling a PI equivalent circuit including the interaction between the sub-model (the model after de-embedding) and the CPW feedings. Extractions for the parasitic elements are performed at four different gate widths ( 2×10 μm, 2×20 μm, 2×30 μm, and 2×70 μm), and our S-parameter prediction shows the best agreement with the measurements in a frequency range of 0.5-110 GHz (0.5 GHz step) among the small-signal models reported to date.

W-band active loads and switching front-end MMICs for radiometer calibration

A millimeter-wave monolithic integrated circuit consisting of a W-band (75–100 GHz) single-pole-five-throw (SP5T) switch and multiple internal active and passive loads for radiometer calibration was designed and manufactured in a low noise 50 nm GaAs metamorphic high electron mobility transistor technology. This highly compact and integrated front-end device for radiometer systems is capable of ultra fast switching between two identical input ports (e.g. for polarimetric applications) and three internal calibration references. It allows an accurate multi-load calibration with noise temperatures between 220 and 1750 K at the output of the device. Compared to conventional calibration methods this marks a substantial advantage in terms of size, mass, power consumption, complexity, and repetition rate.

Investigations on InP/InAlAsSb/GaAs Metamorphic High Electron Mobility Transistors with a Dual-Composition-Graded InxGa1−xAs1−ySby Channel and Different Schottky-Barrier Gate Structures

Device characteristics of InP/In0.34Al0.66As0.85Sb0.15/GaAs metamorphic high electron mobility transistors with a dual-composition-graded InxGa1−xAs1−ySby (x = 0.53 → 0.63 → 0.53, y = 0.01 → 0.02 → 0.01) channel are comprehensively investigated by forming different Schottky-barrier gate structures of Pt/Au-In0.34Al0.66As0.85Sb0.15, Ni/Au-In0.34Al0.66As0.85Sb0.15, or Pt/Au-InP, respectively. Superior device gain, current drive, power, noise, and high-frequency characteristics have been achieved due to relieved kink effects and decreased gate leakages, which are caused by the decreased electron concentration in the channel and suppressed thermionic emission by forming high Schottky-barrier gate structures. High-temperature device characteristics at 300–450 K are also studied. Excellent thermal threshold stability is achieved due to the combinational effects of both barrier-lowering and carrier-carrier scattering mechanisms at high temperatures.

Flip-Chip-Based Multichip Module for Low Phase-Noise $V$-Band Frequency Generation

This paper reports on a flip-chip (FC)-based multichip module (MCM) for low phase-noise (PN) V-band frequency generation. A high-performance ×8 GaAs metamorphic high-electron mobility transistor monolithic microwave integrated circuit (MMIC) multiplier and a low PN 7-GHz GaAs InGaP heterojunction bipolar transistor (HBT) MMIC oscillator were used in the module. The microstrip MMICs were FC bonded to an Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> carrier with patterns optimized for low-loss transitions. The FC-based module was experimentally characterized to have a PN of -88 dBc/Hz @ 100-kHz offset and -112 dBc/Hz @ 1-MHz offset with an output power of 11 dBm. For comparison, the MMICs were also FC bonded as individual chips and the performance was compared with the bare dies without FC bonding. It was verified that the FC bonding has no detrimental effect on the MMIC performance. The tests revealed that the FC module provided improved performance. To our best knowledge, this is the first FC-based module for millimeter-wave frequency generation. The module also presents one of the best PN reported for millimeter-wave frequency sources.

Broadband X-band low noise amplifier based on 70 nm GaAs metamorphic high electron mobility transistor technology for deep space and satellite communication networks and oscillation issues

An X-band low noise amplifier (LNA) using the 70 nm GaAs metamorphic high electron mobility transistors (mHEMT) process available from OMMIC has been reported. The foundry model-based simulated response, on-wafer measurements of the fabricated monolithic microwave integrated circuit (MMIC) LNA and measured data of packaged LNA at room temperature and 100 K have been shown. At room temperature, the packaged LNA exhibits a flat gain more than 26 dB from 7 to 11 GHz with less than 1 dB noise figure at room temperature. The input and output return losses are better than −20 and −10 dB, respectively, between 7.5 and 8.5 GHz. It exhibits linear response with output 1 dB compression point of 1 dBm. MMIC dimension has been limited to 1.5 mm×1 mm. Off-chip inductance in the form of a modelled bondwire has been used to attain the improved input return loss and noise matching. Two figure-of-merits have been proposed and justified, and a comparative study of the overall performances of X-band LNAs with emerging technologies has been made. At 100 K, the LNA shows major improvement of the input and output return losses.

A CPW-Based 77 GHz Power Amplifier with Cascode Structure Using a 130 nm In0.88GaP/In0.4AlAs/In0.4GaAs mHEMTs

In this paper, we present a CPW-based 77 GHz 3-stage power amplifier MMIC for automotive radar systems. The power amplifier MMIC has been realized using a 130 nm <TEX>$In_{0.88}$</TEX>GaP/<TEX>$In_{0.4}$</TEX>AlAs/<TEX>$In_{0.4}$</TEX>GaAs metamorphic high-electron mobility transistors(mHEMTs) technology and an output stage with a cascode configuration. This produced a good output power and gain performance at 77 GHz. The fabricated power amplifier MMIC exhibited a small-signal gain of 18 dB, an output power of 17 dBm and 9 % power added efficiency(PAE) at 77 GHz with a total gate width of 800 <TEX>${\mu}m$</TEX> in the output stage. These performances could be useful to low-cost and small-sized components for 77 GHz automotive radar systems.

High Performance 50 nm InAlAs/In0.75GaAs Metamorphic High Electron Mobility Transistors with Si3N4 Passivation on Thin InGaAs Layer

We fabricated 50 nm InAlAs/InGaAs metamorphic high electron mobility transistors (HEMTs) with a very thin barrier. Through the reduction of the gate–channel distance (dGC) in the epitaxial structure, a channel aspect ratio (ARC) of over three was achieved when Lg was 50 nm. We inserted a thin InGaAs layer as a protective layer, and tested various gate structures to reduce surface problems induced by barrier shrinkage and to optimize the device characteristics. Through the optimization of the gate structure with the thin InGaAs layer, the fabricated 50 nm metamorphic HEMT exhibited high DC and RF characteristics, Gm of 1.5 S/mm, and fT of 490 GHz.

A 220 GHz Single-Chip Receiver MMIC With Integrated Antenna

This letter presents the design and characterization of a 220 GHz microstrip single-chip receiver monolithic microwave integrated circuit (MMIC) with an integrated antenna in a 0.1 mum GaAs metamorphic high electron mobility transistor technology. The receiver MMIC consists of a novel slot-square substrate lens feed antenna, a three-stage low noise amplifier, and a sub-harmonically pumped resistive mixer. The receiver MMIC is mounted on a 12 mm silicon substrate lens which focuses the radiation from the calibration loads to the on-chip antenna through an opening in the backside metallization of the MMIC. The double sideband noise figure of this quasioptical receiver is as low as 8.4 dB (1750 K) at 220 GHz including the losses in the antenna and in the lens. To the best of the authors' knowledge, this work demonstrates the highest integration level versus operating frequency for a MMIC ever published, regardless of technology.

Influence of V/III ratio on the structural and photoluminescence properties of In0.52AlAs/In0.53GaAs metamorphic high electron mobility transistor grown by molecular beam epitaxy

A series of metamorphic high electron mobility transistors (MMHEMTs) with different V/III flux ratios are grown on GaAs (001) substrates by molecular beam epitaxy (MBE). The samples are analysed by using atomic force microscopy (AFM), Hall measurement, and low temperature photoluminescence (PL). The optimum V/III ratio in a range from 15 to 60 for the growth of MMHEMTs is found to be around 40. At this ratio, the root mean square (RMS) roughness of the material is only 2.02 nm; a room-temperature mobility and a sheet electron density are obtained to be 10610.0cm2/(V·s) and 3.26 × 1012cm−2 respectively. These results are equivalent to those obtained for the same structure grown on InP substrate. There are two peaks in the PL spectrum of the structure, corresponding to two sub-energy levels of the In0.53Ga0.47As quantum well. It is found that the photoluminescence intensities of the two peaks vary with the V/III ratio, for which the reasons are discussed.

High-temperature threshold characteristics of a symmetrically graded InAlAs∕InxGa1−xAs∕GaAs metamorphic high electron mobility transistor

High-temperature threshold characteristics of a symmetrically graded δ-doped InAlAs∕InxGa1−xAs∕GaAs (x=0.5→0.65→0.5) metamorphic high electron mobility transistor (MHEMT) have been investigated. The thermal threshold coefficients, defined as ∂Vth∕∂T, are superiorly low at 0.9mV∕K from 300to420K and at −0.75mV∕K from 420to500K. An interesting polarity change of the thermal threshold coefficient was observed around 420K due to the variation of thermal modulation effects. The present MHEMT device, with stabilized thermal threshold variations and superior high-temperature linearity characteristics, is promising for high-temperature circuit applications.

High-performance 0.1-/spl mu/m In/sub 0.4/AlAs/In/sub 0.35/GaAs MHEMTs with Ar plasma treatment

High-performance 0.1-/spl mu/m In/sub 0.4/AlAs/In/sub 0.35/GaAs metamorphic high-electron mobility transistors (MHEMTs) on GaAs substrate have been successfully fabricated with Ar plasma treatment. Before the gate Schottky metallization, the devices were treated with Ar plasma, which might clean and improve the surface of exposed barrier layer. The devices fabricated with Ar plasma treatment exhibited the excellent characteristics such as 50% reduction of the reverse gate leakage currents, the improved Schottky ideality factor of 1.37, high extrinsic transconductance of 700 mS/mm, and high maximum drain current density of 780 mA/mm. And the cutoff frequency f/sub T/ as high as 210 GHz was achieved. To our knowledge, this is the best reported cutoff frequency for a 0.1-/spl mu/m MHEMT with an indium content of 35% in the channel.

High-temperature thermal stability performance in /spl delta/-doped In/sub 0.425/Al/sub 0.575/As--In/sub 0.65/Ga/sub 0.35/As metamorphic HEMT

We report, to our knowledge, the best high-temperature characteristics and thermal stability of a novel /spl delta/-doped In/sub 0.425/Al/sub 0.575/As--In/sub 0.65/Ga/sub 0.35/As--GaAs metamorphic high-electron mobility transistor. High-temperature device characteristics, including extrinsic transconductance (g/sub m/), drain saturation current density (I/sub DSS/), on/off-state breakdown voltages (BV/sub on//BV/sub GD/), turn-on voltage (V/sub on/), and the gate-voltage swing have been extensively investigated for the gate dimensions of 0.65×200 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The cutoff frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> ) and maximum oscillation frequency (f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> ), at 300 K, are 55.4 and 77.5 GHz at V/sub DS/=2 V, respectively. Moreover, the distinguished positive thermal threshold coefficient (/spl part/V/sub th///spl part/T) is superiorly as low as to 0.45 mV/K.