GaAs Metamorphic High-electron Mobility Transistor Research Articles

Self-heating of cryogenic high electron-mobility transistor amplifiers and the limits of microwave noise performance

The fundamental limits of the microwave noise performance of high electron-mobility transistors (HEMTs) are of scientific and practical interest for applications in radio astronomy and quantum computing. Self-heating at cryogenic temperatures has been reported to be a limiting mechanism for the noise, but cryogenic cooling strategies to mitigate it, for instance, using liquid cryogens, have not been evaluated. Here, we report microwave noise measurements of a packaged two-stage amplifier with GaAs metamorphic HEMTs immersed in normal and superfluid 4He baths and in vacuum from 1.6 to 80 K. We find that these liquid cryogens are unable to mitigate the thermal noise associated with self-heating. Considering this finding, we examine the implications for the lower bounds of cryogenic noise performance in HEMTs. Our analysis supports the general design principle for cryogenic HEMTs of maximizing gain at the lowest possible power.

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.

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.

22 nm InAs channel-based HEMTs on InP/GaAs substrates for future THz applications

In this work, the performance of nm InAs channel-based high electron mobility transistor (HEMT) on InP substrate is compared with metamorphic high electron mobility transistor (MHEMT) on GaAs substrate. The devices features heavily doped InAs source/drain (S/D) regions, Si double δ-doping planar sheets on either side of the InAs channel layer to enhance the transconductance, and buried Pt metal gate technology for reducing short channel effects. The TCAD simulation results show that the InP HEMT performance is superior to GaAs MHEMT in terms of , and transconductance (). The 22 nm InP HEMT shows an of 733 GHz and an of 1340 GHz where as in GaAs MHEMT it is 644 GHz and 924 GHz, respectively. InGaAs channel-based HEMTs on InP/GaAs substrates are suitable for future sub-millimeter and millimeter wave applications.

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.

A Gate-Width Scalable Method of Parasitic Parameter Determination for Distributed HEMT Small-Signal Equivalent Circuit

We propose a gate-width scalable method for extracting the reliable parasitic elements of the 0.1- μm GaAs metamorphic high electron-mobility transistors. This method utilizes the de-embedding scheme for coplanar waveguide (CPW) feeding structure by considering the distributed extrinsic parasitic elements in our small-signal model. The parasitic capacitances are determined based on estimation of the sub-model (the model after de-embedding the contribution of the CPW feeding structure). We perform the parameter extraction at four different gate widths of the devices to examine the scaling effect. The model shows the best S-parameter effective fitting error of 9.85% among four different extraction methods evaluated in this study over the entire gate-width variation and in a frequency range of 0.5-110 GHz.

Single-Chip 220-GHz Active Heterodyne Receiver and Transmitter MMICs With On-Chip Integrated Antenna

This paper presents the design and characterization of single-chip 220-GHz heterodyne receiver (RX) and transmitter (TX) monolithic microwave integrated circuits (MMICs) with integrated antennas fabricated in 0.1- μm GaAs metamorphic high electron-mobility transistor technology. The MMIC receiver consists of a modified square-slot antenna, a three-stage low-noise amplifier, and a sub-harmonically pumped resistive mixer with on-chip local oscillator frequency multiplication chain. The transmitter chip is the dual of the receiver chip by inverting the direction of the RF amplifier. The chips are mounted on 5-mm silicon lenses in order to interface the antenna to the free space and are packaged into two separate modules.

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.

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.

Single-Chip Frequency Multiplier Chains for Millimeter-Wave Signal Generation

Two single-chip frequency multiplier chains targeting 118 and 183 GHz output frequencies are presented. The chips are fabricated in a 0.1 ?m GaAs metamorphic high electron-mobility transistor process. The D-band frequency doubler chain covers 110 to 130 GHz with peak output power of 5 dBm. The chip requires 2 dBm input power and consumes only 65 mW of dc power. The signal at the fundamental frequency is suppressed more than 25 dB compared to the desired output signal over the band of interest. The G-band frequency sextupler (×6) chain covers 155 to 195 GHz with 0 dBm peak output power and requires 6.5 dBm input power and 92.5 mW dc power. The input signal to the multiplier chain can be reduced to 4 dBm while the output power drops only by 0.5 dB. The unwanted harmonics are suppressed more than 30 dB compared to the desired signal. An additional 183 GHz power amplifier is presented to be used after the ×6 frequency multiplier chain if higher output power is required. The amplifier delivers 5 dBm output power with a small-signal gain of 9 dB from 155 to 195 GHz. The impedance matching networks are realized using coupled transmission lines which is shown to be a scalable and straightforward structure to use in amplifier design. Microstrip transmission lines are used in all the designs.

Fabrication of 0.15-$\mu\hbox{m}$$\Gamma$-Shaped Gate $\hbox{In}_{0.52}\hbox{Al}_{0.48}\hbox{As}/\hbox{In}_{0.6}\hbox{Ga}_{0.4}\hbox{As}$ Metamorphic HEMTs Using DUV Lithography and Tilt Dry-Etching Technique

An 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">0.6</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4 </sub> As metamorphic high-electron mobility transistor (MHEMT) with 0.15-mum Gamma-shaped gate using deep ultraviolet lithography and tilt dry-etching technique is demonstrated. The developed submicrometer gate technology is simple and of low cost as compared to the conventional E-beam lithography or other hybrid techniques. The gate length is controllable by adjusting the tilt angle during the dry-etching process. The fabricated 0.15-mum 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">0.6</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4</sub> As MHEMT using this novel technique shows a saturated drain-source current of 680 mA/mm and a transconductance of 728 mS/mm. The f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> and f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> of the MHEMT are 130 and 180 GHz, respectively. The developed technique is a promising low-cost alternative to the conventional submicrometer E-beam gate technology used for the fabrication for GaAs MHEMTs and monolithic microwave integrated circuits

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.

K-band receiver front-ends in a GaAs metamorphic HEMT process

In this paper, we present K-band receiver blocks fabricated in a state-of-the-art 0.18-/spl mu/m GaAs metamorphic high electron-mobility transistor (MHEMT) process using a 60% indium-content InGaAs channel. Several circuits are developed to demonstrate the superior noise performance and successful integration of K-band receiver components in such a process. We show a low-power three-stage low-noise amplifier (LNA) with a gain of 23 dB and a noise figure (NF) of less than 1.6 dB at 30 GHz. This LNA shows InP-like performance on a GaAs substrate with a high RF yield of 84%. This is the first report of a statistical yield analysis of an MHEMT integrated circuit. We also demonstrate on-chip integration of a single-stage amplifier with a diode subharmonic mixer for low-power and broad-band receiver performance. This down-converter exhibits a conversion loss of 3 dB, overall NF of 5 dB, and third-order input intercept point of -5 dBm from 26 to 30 GHz.