Metamorphic HEMT Technology Research Articles

A 50-nm Gate-Length Metamorphic HEMT Technology Optimized for Cryogenic Ultra-Low-Noise Operation

This article reports on the investigation and optimization of cryogenic noise mechanisms in InGaAs metamorphic high-electron-mobility transistors (mHEMTs). HEMT technologies with a gate length of 100, 50, and 35 nm are characterized both under room temperature and cryogenic conditions. Furthermore, two additional technology variations with 50-nm gate length are investigated to decompose different noise mechanisms in HEMTs. Therefore, cryogenic extended Ku-band low-noise amplifiers of the investigated technologies are presented to benchmark their noise performance. Technology C with a 50-nm gate length exhibits an average effective noise temperature of 4.2 K between 8 and 18 GHz with a minimum of 3.3 K when the amplifier is cooled to 10 K. The amplifier provides an average gain of 39.4 dB at optimal noise bias. The improved noise performance has been achieved by optimization of the epitaxial structure of the 50-nm technology, which leads to low gate leakage currents and high gain at low drain current bias. To the best of the authors' knowledge, this is the first time that an average noise temperature of 4.2 K has been demonstrated in the Ku-band.

Low-Loss Millimeter-Wave SPDT Switch MMICs in a Metamorphic HEMT Technology

This letter presents the design and performance of two single-pole double-throw (SPDT) switches operating in $V$ -band (50–75 GHz) and $W$ -band (75–110 GHz). The millimeter-wave (mmW) integrated circuits (MMICs) are fabricated in a 50-nm gate-length metamorphic high-electron-mobility transistor technology. Special attention was paid to the reduction of the insertion loss (IL). Thus, both switch MMICs achieve an IL of 1–1.6 dB (average 1.2 dB), covering the entire $V$ -band and $W$ -band, respectively. The isolation (ISO) of the switches is better than 31.6 and 28.5 dB, respectively. The input power for 1 dB of IL compression is at least 22 and 19 dBm, respectively. A wafer mapping of both circuits exhibits a high yield and low spread of IL and ISO. Based on the given results, the presented SPDT switch MMICs demonstrates state-of-the-art performance.

Frequency Multiplier and Mixer MMICs Based on a Metamorphic HEMT Technology Including Schottky Diodes

This paper reports on the monolithic integration of layout-optimized Schottky diodes realized in an established 50-nm gate-length metamorphic high-electron-mobility transistor technology for use in multifunctional nonlinear circuits. The suitability of the realized Schottky diodes is demonstrated by a broadband millimeter-wave I/Q-mixer (In-phase/Quadrature) and local oscillator (LO) chain comprising two power amplifiers and a frequency tripler, fabricated on monolithic microwave integrated circuits (MMICs). Both circuits are based on an anti-parallel Schottky diode topology. The subharmonically-pumped I/Q-mixer covers an RF (radio frequency) and IF (intermediate frequency) range of at least 75 GHz to 110 GHz and 0.5 GHz to 15 GHz, respectively. The single-sideband conversion loss is between 14 dB and 16 dB across most of the entire RF and IF bands. The core of the LO chain consists of a frequency tripler (multiplier by three) and features a bias-adjustable output power with almost constant conversion efficiency and a control range of more than 8 dB. The fully-integrated LO chain MMIC matches the needs of the presented I/Q-mixer and exhibits an average output power of 16.3 dBm with a covered frequency range of 38 GHz to 60 GHz. The unwanted harmonics are suppressed by at least -25.9 dBc below the third harmonic for the entire frequency range and better than -32.1 dBc for most part of the band. Thus, the mixer and tripler MMICs demonstrate state-of-the-art performance with regards to, e.g., covered bandwidth, output power, harmonic suppression, or 1 dB compression point.

A Miniaturized Unit Cell for Ultra-Broadband Active Millimeter-Wave Frequency Multiplication

A compact broadband unit cell for the design of broadband frequency multipliers is presented. Based on design methods from moderate frequencies, a novel integrated balanced field-effect transistor architecture is introduced, pushing ultra-broadband balanced frequency multiplication into the high millimeter-wave range. The realized microwave monolithic integrated circuits (MMICs) using this topology provide second harmonic generation over several decades using only a single integrated transistor unit cell. The circuits are fabricated in a metamorphic HEMT technology for convenient integration into multifunctional MMICs and achieve relative bandwidths of 199% from 60 MHz to 80 GHz and 70.1% in $D$ - and $G$ -band (110–170 and 140–220 GHz).

243 GHz low-noise amplifier MMICs and modules based on metamorphic HEMT technology

Two compact H-band (220–325 GHz) low-noise millimeter-wave monolithic integrated circuit (MMIC) amplifiers have been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 50 and 35 nm metamorphic high electron mobility transistors (mHEMTs). For low-loss packaging of the circuits, a set of waveguide-to-microstrip transitions has been realized on 50-μm-thick GaAs substrates demonstrating an insertion loss of <0.5 dB at 243 GHz. By applying the 50 nm gate-length process, a four-stage cascode amplifier module achieved a small-signal gain of 30.6 dB at 243 GHz and more than 28 dB in the bandwidth from 218 to 280 GHz. A second amplifier module, based on the 35-nm mHEMT technology, demonstrated a considerably improved gain of 34.6 dB at 243 GHz and more than 32 dB between 210 and 280 GHz. At the operating frequency, the two broadband low-noise amplifier modules achieved a room temperature noise figure of 5.6 dB (50 nm) and 5.0 dB (35 nm), respectively.

A 243 GHz LNA Module Based on mHEMT MMICs With Integrated Waveguide Transitions

For use in a millimeter-wave direct detection radiometer for earth remote sensing, we have developed a low-noise amplifier (LNA) module with a small-signal gain of 19.5 dB at 243 GHz and a 3 dB bandwidth of 40 GHz. The implemented three-stage LNA MMIC has been manufactured using a 50 nm gate length metamorphic HEMT (mHEMT) technology on 50 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu$</tex> </formula> m thick GaAs substrates. Each of the two on-chip integrated E-plane probe waveguide transitions offers a transmission loss of only 0.5 dB at 243 GHz including a 7.5 mm long WR-3.4 waveguide. Due to the low-loss packaging, the LNA module achieves a low noise figure of only 6.0 dB at room temperature.

Development of Monolithic Microwave Integrated Amplifiers as Readout for Detectors at 4.2 K

Readout amplifiers with high bandwidth and extremely low power dissipation at liquid helium temperature for various superconducting detectors (e.g. SNSPD, HEB and MKID) are necessary to increase the small detector output signals. Different types of cryogenic amplifiers were developed for these applications. The required combination of low noise, large bandwidth, high voltage gain and low power consumption is a driving force for an on-going process of improvements. In this paper, the developments of cryogenic low power hybrid amplifiers, which are based on commercial p-HEMT transistors, will be reported and discussed. In addition, simulation and measurement results of the first developed monolithic microwave integrated circuit (MMIC) amplifier for low power operation will be presented. The MMICs are based on a metamorphic HEMT technology and are realized on a 3×1.5 mm2 area. First measurements at room temperature showed a bandwidth of 0.3 GHz up to 9 GHz with a gain of 23 dB at 90 mW and 1.3 GHz up to 8 GHz with 20 dB of gain at 42 mW, respectively. The power consumption could be reduced by cooling the devices down to 7.2 K. At almost identical bandwidths, the measured gain decreased to 10 dB at 22 mW and 15 dB at 9.5 mW.

A W-Band $\times$12 Multiplier MMIC With Excellent Spurious Suppression

This letter presents a single chip × 12 frequency multiplier MMIC for the W-band that is realized in a 100 nm metamorphic HEMT technology. To obtain the × 12 multiplication factor a multiplier chain of a doubler, a tripler and a doubler has been cascaded. The circuit has a 3 dB bandwidth of 15 GHz from 85 to 100 GHz. At 94 GHz, the multiplier achieves a saturated output power of more than 1 dBm and a conversion gain of 0 dB. The suppression of unwanted harmonics is better than 30 dBc at 94 GHz and better than 24 dBc within the entire bandwidth.

A 200 GHz Monolithic Integrated Power Amplifier in Metamorphic HEMT Technology

A millimeter-wave monolithic integrated circuit power amplifier operating in the frequency range between 186 and 212 GHz is presented. The amplifier, dedicated to high-resolution imaging radar and communication systems, is realized in a 100 nm gate length metamorphic high electron mobility transistor technology. The three-stage design with four parallel transistors in the output stage achieves a linear gain of more than 12 dB and provides a saturated output power of more than 9 dBm and 7 dBm at 192 and 200 GHz, respectively.

Analysis and Design of a Novel $\times$4 Subharmonically Pumped Resistive HEMT Mixer

In this paper, a novel topology of an HEMT-based subharmonically pumped resistive mixer (SHPRM) is presented, i.e., the times4SHPRM. The presented topology requires only a quarter of the local oscillator (LO) frequency compared to a fundamentally pumped mixer (e.g., 15 instead of 60 GHz in a 60-GHz system). This reduction in required LO frequency provides a significant reduction in complexity of the overall radio front-end and reduces the dc power consumption as well as the occupied chip area. Thus, the times4SHPRM provides a significant cost reduction for a millimeter-wave system. Furthermore, the times4SHPRM can be used for both up- and down-conversion and it can be implemented in any field-effect transistor technology. The principle of the times4SHPRM is presented and wave analysis is applied in order to investigate the fundamental limitations of this mixer topology. For an evaluation of the times4SHPRM topology, three different monolithic microwave integrated circuits (MMICs) were designed and manufactured in the same MMIC metamorphic HEMT technology. Besides measured performance of the times4SHPRM, a traditional times2SHPRM and a single-ended resistive mixer were implemented and their performances are presented and compared. All of these MMICs operate with a 60-GHz RF frequency and employ LO signals close to 15, 30, and 60 GHz, respectively.

A distributed amplifier with 12.5‐dB gain and 82.5‐GHz bandwidth using 0.1 μm GaAs metamorphic HEMTs

AbstractIn this letter, the monolithic distributed amplifier with active control scheme is presented, using 0.1 μm GaAs metamorphic HEMT technology, with a maximum operating frequency of 315 GHz. Active feedback resistor, which adjusts the negative resistance generated by the cascode gain cell, is employed to maximize the bandwidth of the entire distributed amplifier without oscillation. The measurement of the distributed amplifier with 5 cascode gain cells shows the gain of 12.5 ± 1.2 dB and 3‐dB bandwidth of 82.5 GHz corresponding to the ultrahigh gain‐bandwidth product of 347 GHz. Group delay variation is also measured to be less than ±8.9 ps up to 60 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2873–2875, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22844

A high‐power MMIC VCO utilizing metamorphic HEMT technology

AbstractA high‐power monolithic microwave integrated circuit voltage controlled oscillator (MMIC VCO) that can drive optical devices such as an electro‐absorption and an electro‐optic modulators is presented. A common‐gate metamorphic HEMT (MHEMT) with 0.2 mm of gate width in conjunction with inductive feedback was used to generate negative resistance. The low‐loss coplanar waveguide transmission line on the 650 μm‐thick metamorphic GaAs substrate was utilized to minimize loss. The maximum generated output power of the MHEMT VCO was 40.1 mW at 24.1 GHz when biased at Vds = 3.8 V and Vgs = −0.44 V. Phase noise and frequency tuning range were estimated to be −93.4 dBc/Hz at 1 M Hz offset and 1 GHz, respectively. Experimental results show great promise for the MHEMT MMIC VCO to be used in future high‐power microwave source applications especially for driving optical devices. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2221–2224, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22702

220 GHz low‐noise amplifier MMICs and modules based on a high performance 50 nm metamorphic HEMT technology

A metamorphic composite-channel InAlAs/InGaAs based high electron mobility transistor (MHEMT) technology has been developed for active and passive high-resolution imaging applications. The technology features 50 nm gate length in combination with an In content of 80% in the main channel and 53% in the second channel. An extrinsic transit frequency ft of 400 GHz and an extrinsic maximum transconductance gm,max of 1800 mS/mm were measured at a drain voltage of 1 V. Based on this advanced MHEMT technology, coplanar G-band low-noise amplifier (LNA) MMICs were realized, achieving a small-signal gain of more than 15 dB between 192 and 230 GHz together with an average noise figure of 8 dB. Furthermore, mounting and packaging of the monolithic amplifier chips into G-band waveguide modules was accomplished with only minor reduction in circuit performance. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

High power 60 GHz push push oscillator using InALAs/InGaAs metamorphic HEMT technology

AbstractThis paper reports a high power 60 GHz push–push oscillator fabricated using 0.12 μm GaAs metamorphic high electron‐mobility transistors. By combining high‐power metamorphic high electron mobility transistor (MHEMT) optimized for millimeter‐wave operation and push–push technique, the oscillator achieved 7.4 dBm of output power at 59 GHz with 37 dBc fundamental frequency suppression. To the knowledge of the authors, this is the first monolithic push–push oscillator at V‐band fabricated using MHEMT technology. Also, the 7.4 dBm of output power is the largest for any oscillators based on MHEMT in this frequency range, and compares well to the result obtained from mature GaAs PHEMT technology. The results demonstrate the application of high power MHEMT for cost effective millimeter‐wave commercial applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 609–612, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22203

W-band divide-by-3 frequency divider using 0.1 µm InAlAs/InGaAs metamorphic HEMT technology

A W-band divide-by-3 frequency divider with wide bandwidth and low power dissipation is presented using harmonic injection-locking technique. A cascode FET is employed for a self-oscillating second-harmonic mixer which is injection-locked by third-harmonic input to obtain the division order of three. The fabricated frequency divider using 0.1 µm GaAs metamorphic HEMT technology shows superior performance such as large bandwidth of 6.1 GHz around 83.1 GHz (7.3%) under small DC power consumption of 12 mW.

A D-band frequency doubler MMIC based on a 100-nm metamorphic HEMT technology

A coplanar single-ended frequency doubler based on a 100 nm metamorphic HEMT technology is presented. For an input power of 4.8 dBm, this doubler demonstrates an output power between 2.6 and -0.3 dBm over the bandwidth from 105 to 145 GHz, that is, a 3-dB bandwidth of 32% has been achieved. To the knowledge of the authors, this is the first reported multiplier based on MHEMT technology at D-band or higher frequencies.

W-band resistive mixer using metamorphic HEMT

We fabricate single-ended resistive W-band millimeter-wave monolithic IC (MIMIC) mixers based on 0.1 μm InGaAs/InAlAs/GaAs metamorphic HEMT technology. The mixers show good characteristics in linearity and LO-RF isolation, and the mixers with IF amplifiers exhibit a conversion loss of ∼0.4 dB, which is an improvement of ∼7.8 dB compared to that of the mixers without IF amplifiers. We obtain P-1 dB of 10 and 9 dBm from the mixers with and without the IF amplifiers, respectively.

Reliability of 50 nm low-noise metamorphic HEMTs and LNAs

The long-term stability of a 50 nm low-noise metamorphic HEMT technology has been investigated by biased accelerated lifetime tests on both MHEMT devices and two-stage LNAs for W-band applications. The lifetime tests were performed at three channel temperatures, a drain voltage of 1 V and a power density of 0.3 W/mm in air. Based on a −10% degradation of gm max failure criterion an activation energy of 1.6 eV and a projected median lifetime of 2.7×106 h at Tch=125°C were determined. The two-stage LNAs were stressed at a channel temperature of 185°C for 4000 h. The S-parameters did not show any significant degradation after 4000 h of stress time if the positive threshold voltage shift was compensated for by a corresponding increase of the gate voltage. The reliability results demonstrate the stable operation of 50 nm MHEMTs and LNAs for W-band applications and beyond.

METAMORPHIC LOW NOISE AMPLIFIERS AND OPTICAL COMPONENTS

GaAs based metamorphic HEMT (MHEMT) technology has emerged as an attractive, low cost alternative to InP HEMTs. The strain-induced imperfections caused by high indium content layers on GaAs is eliminated in metamorphic devices by providing a properly grown lattice-matching buffer between the substrate and active device layers. With this limitation overcome, it is now possible to provide the superior performance of InP-based devices with the cost advantages of highly manufacturable 4- and 6-inch GaAs wafers that can easily be integrated on existing GaAs fabrication lines. This paper will review device performance as well as state-of-the-art low noise amplifiers fabricated with this technology operating from 1 to 100 GHz. Fiber optic receiver components such as 40 Gb/s optical-to-electrical photodiodes and traveling wave amplifiers fabricated metamorphically will also be discussed. Finally, device and circuit reliability data will be presented demonstrating median-time-to-failure of more than 30 years at 125 C.

Reliability of metamorphic HEMTs on GaAs substrates

Metamorphic HEMT (MHEMT) technology enables the growth of high indium content channels on GaAs substrates, giving them the performance of InP HEMTs. MHEMT growth techniques use a graded alloy composition buffer layer structure, permitting channel indium contents exceeding 25% without strain. Potential applications include 40 Gb/s fiber optic receivers as well as LNAs for local multipoint distribution systems and satellite communications. Many such applications place stringent requirements on reliability with Belcore standards requiring 10 6 h median time to failure (MTTF) at 125 °C for power devices. Satellite applications require a LNA projected failure-free service of 15–30 years, implying approximately 10 7 h MTTF, at 85 °C. Naturally, one will ask “Is MHEMT technology reliable?” From the results of our ongoing work, we show that MHEMT reliability is similar to that of InP HEMTs with ∼10 6 h MTTF at 125 °C.