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Schottky contacts on fluorine implanted AlGaN/GaN heterostructures with the ideality factor close to unity and low on-voltage threshold are presented in this paper. An SF6 plasma anode pretreatment followed by a specific low-temperature annealing is also compared to a nonannealed sample. In addition, physical-model parameters are extracted by means of cryogenic temperature measurements to understand the conduction mechanisms involved in annealed diodes, showing better DC performances than their nonannealed counterparts. Furthermore, annealing induces a decrease of the ideality factor, which sets the field-enhanced thermionic emission as the main conduction mechanism, and reduces the tunneling reverse current leakage. This effect is attributed to the recovery of the plasma-induced damages. [ABSTRACT FROM AUTHOR]

In this paper, the slow‐wave coplanar stripline (S‐CPS) technology is utilised to design high performance and small footprint resonators operating within the millimetre‐wave band from 50 to 80 GHz. The proposed resonators are designed based on high quality factor quasi‐lumped capacitances and inductances offering a great flexibility in terms of design. The derivation of these components from the S‐CPS is explained theoretically and their behaviour is validated by EM simulation; an equivalent electrical model is also developed. The proposed concepts are demonstrated in the BiCMOS 55‐nm technology, and a good agreement between modelling, EM simulation and measurement results is achieved. The proposed devices could later be considered as interesting elementary blocks for the design of mm‐wave filters. [ABSTRACT FROM AUTHOR]

The design and experimental results of millimeter-wave bandpass filters (BPFs) implemented in 55-nm BiCMOS technology and operating around 120 GHz are presented in this article. Slightly modified coupled line filters’ structures are used in the designs. It allows generating the transmission zero at the upper stopband, leading to the selectivity of enhanced filters. The coupled line structure is implemented in two technologies, microstrip coupled lines and coupled slow-wave (SW) coplanar waveguides (CS-CPWs). The latter shows more design flexibility, allowing to reach a better filtering performance than the microstrip filters, i.e., better in-band flatness and higher selectivity. Good agreement is achieved between simulation, modeling, and measurement results. Also, the overall length of the filter based on CS-CPWs is smaller as compared to the filters based on the microstrip lines, thanks to the SW propagation. [ABSTRACT FROM AUTHOR]

THz sources based on the optical-heterodyne (photo)mixing in an ultrafast photodetector are very promising since they operate at room temperature, are potentially compact, cost-efficient and, above all, are widely frequency-tunable. However, their widespread use is currently hampered by available power levels in the μW range at THz frequencies. We present here a travelling wave structure, with millimeter level coherence length at THz frequencies opening the way to large active area (∼4000 μm2) photomixing devices capable of handling optical pump power beyond 1 W well beyond the capabilities of standard lumped-element devices using small active areas (<50 μm2) needed to maintain a capacitance level (<10 fF) compatible with THz operation. It is based on a silicon nitride waveguide coupled to a membrane-supported low-temperature-grown GaAs photoconductor embedded in a coplanar waveguide. Milliwatt power levels up to 1 THz and still above 1 μW up to 4 THz are expected according to the optoelectronics model of this device elaborated in this study. Experimentally, the frequency response of a 1-mm-long structure, measured up to 100 GHz by using the beatnote produced by two 780-nm-DFB lasers, shows clearly the expected travelling wave signature consisting in a 6-dB-decrease ending at ∼50 GHz when the contribution of the backward travelling wave is fully cancelled, following by a constant level up to ∼100 GHz. The experimental demonstration of operation in the travelling wave regime is a first step towards the fulfillment of the original promises of this concept in terms of power level and frequency bandwidth. [ABSTRACT FROM AUTHOR]

This article presents the design and characterization of a real-time frequency-compensated power detector (PD), based on NMOS transistor, integrated in SiGe 55-nm BiCMOS technology from STMicroelectronics, and dedicated to on-chip power detection in the G-band frequencies. An innovative simple circuit (named attenuator) is designed in order to compensate the variation of the voltage sensitivity value with frequency, which is established by exhibiting lower attenuation (smaller real part impedance) at higher frequencies. As a result, the measured sensitivity value is compensated with a small variation (1800 V/W±10%) over the frequency band (140-220) GHz. To the best of the authors’ knowledge, this detector is the first design which proposes a real-time frequency compensation at such high- and large-frequency bands. The attenuator was also designed to exhibit an inductive impedance (in the G-band) in order to compensate the capacitive effect of the NMOS, which helps to use smaller NMOS size and, therefore, obtain a higher sensitivity value. Compared to recent works, our detector exhibits a performance belong the current state-of-the-art with a very low noise equivalent power (NEP) value 4.56 pW/√ Hz and a relatively high voltage sensitivity value. [ABSTRACT FROM AUTHOR]

This article focuses on the design of high-performance coupled slow-wave coplanar waveguide (CS-CPW) in CMOS technologies for the millimeter-wave (mm-wave) frequency bands. First, the theory as well as the electrical model of the CS-CPW are presented. Next, the analytical approach for the calculation of the model parameters is discussed. Then, by using the developed model, two mm-wave backward directional 3-dB couplers are designed in a bipolar complementary metal–oxide–semiconductor (BiCMOS) 55-nm technology for 120- and 185-GHz operation, respectively. Simulation and experimental results demonstrate that the use of the CS-CPW concept leads to state-of-the-art performance, with a good agreement between the analytical model, electromagnetic simulations, and measurement results. [ABSTRACT FROM AUTHOR]

The ability to realize flexible circuits integrating sensing, signal processing, and communicating capabilities is of central importance for the development of numerous nomadic applications requiring foldable, stretchable, and large area electronics. A key challenge is, however, to combine high electrical performance (i.e., millimeter wave, low noise electronics) with mechanical flexibility required for chip form adaptivity in addition to highly stable electrical performance upon deformation. Here, we describe a solution based on ultimate thinning and transfer onto a plastic foil of high frequency CMOS devices initially processed on conventional silicon-on-insulator wafers. We demonstrate a methodology relying on neutral plane engineering to provide high performance stability upon bending, by locating the active layer, i.e., the transistor channel, at the neutral fiber of the flexible system. Following this strategy, record frequency performance of flexible n-MOSFETs, featuring fT/fMAX of 120/145 GHz, is reported with relative variations limited to less than 5% even under aggressive bending on cylinders with curvature radii down to 12.5 mm. [ABSTRACT FROM AUTHOR]

This article presents the design, experimental results, and modeling of an inversion-mode CMOS varactor integrated in the STMicroelectronics 55-nm BiCMOS technology. The device was characterized from 1 to 325 GHz, demonstrating high-quality factor at millimeter-waves. For instance, a quality factor of 7 at around 190 GHz for a tuning ratio (Cmax/Cmin) greater than 4 was measured. This performance overpasses that of accumulation-mode varactors usually provided in CMOS technologies design kits, for frequencies beyond about 100 GHz. In addition, a small-signal electrical model is provided from 100 to 250 GHz. [ABSTRACT FROM AUTHOR]

In this article, the electrical model of a millimeter-wave (mmW), silicon-based noise source is developed in the frequency range up to 325 GHz. The model is studied as a function of the biasing current and the structure size. The noise source is based on a Schottky diode realized on the 55-nm SiGe BiCMOS technology from STMicroelectronics, Crolles, France. Due to the ability of being integrated on silicon, this noise source can be used for high-frequency in situ noise characterization of advanced silicon CMOS or bipolar technologies in the mmW range. In previous study, the diode was used as a noise source when biased near the avalanche regime, and an excess noise ratio (ENR) up to 20 dB has been achieved in a frequency range up to 260 GHz. In this article, the ENR value of the diode is retrieved from the electrical model and compared to the value extracted by measurements. The extracted ENR value was also studied for several diode sizes and biasing currents and measured up to 325 GHz, with a good agreement with the modeling. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) nanoscale crystal shaping has become essential for the precise design of advanced electronic and quantum devices based on electrically gated transport. In this context, III-V semiconductor-based nanowires with low electron effective mass and strong spin-orbit coupling are particularly investigated because of their exceptional quantum transport properties and the good electrostatic control they provide. Among the main challenges involved in the processing of these nanodevices are (i) the management of the gate stack which requires ex-situ passivation treatment to reduce the density of traps at the oxide/semiconductor interface, (ii) the ability to get good ohmic contacts for source and drain electrodes and (iii) the scalability and reliability of the process for the fabrication of complex architectures based on nanowire networks. In this paper, we show that selective area molecular beam epitaxy of in-plane InGaAs/InP core-shell nanowires with raised heavily doped source and drain contacts can address these different issues. Electrical characterization of the devices down to 4 K reveals the positive impact of the InP shell on the gate electrostatic control and effective electron mobility. Although comparable to the best reported values for In(Ga)As nanostructures grown on InP, this latter is severely reduced for sub-100 nm channel highlighting remaining issue to reach the ballistic regime. [ABSTRACT FROM AUTHOR]

The dielectric dispersion of ferroelectric BaxSr1-xTiO3 (BST) thin film in a paraelectric phase was characterized from centimeter to submillimeter wavelengths. To this aim, interdigitated capacitors were patterned on a micrometer scale onto a BST layer with a barium concentration of 0.5 and were subsequently integrated by using a coplanar waveguide technology. The retrieval of the complex permittivity of BST was performed by vectorial scattering parameter measurements up to 190 GHz for various controlling dc field up to 300 kV/cm. At higher frequency, submillimeter wavelength measurements were performed by time domain spectroscopy under free space condition. On this basis, the dispersion of the real part of the permittivity along with the loss tangent are retrieved in agreement with a distributed interaction of ac-field with soft phonons vibration modes, and overlapping between dipole polarization and ionic polarization is observed, around 700 GHz. It is also shown that dipole polarization can be attributed to the presence of small polar nanoregions in the BST film which act as in ferroelectric material with diffuse phase transition. [ABSTRACT FROM AUTHOR]

This paper describes the development and characterization of a millimeter-wave (mmW) integrated noise source development on silicon technology for applications up to 260 GHz. The developed integrated noise source is based on p-n and Schottky junction in series, realized on the SiGe BiCMOS 55-nm technology from STMicroelectronics. Biased in the avalanche regime, this integrated diode noise source achieves a tunable excess noise ratio (ENR) ranged between 0 dB and 15 dB, in the 130–260-GHz frequency range. In order to highlight the usefulness of the integrated noise source, the noise figure of two amplifiers was measured: the first one is an integrated low-noise amplifier (LNA) operating in the D-band (130–170 GHz) while the second one is packaged and operates from 220 to 260 GHz. Due to its ability to be naturally integrated on silicon, this noise source features a strong interest to carry out high-frequency in situ noise characterization of advanced Si CMOS or BiCMOS technologies in the mmW range. [ABSTRACT FROM AUTHOR]

In this paper we present high frequency field effect transistors based on graphene nanoribbons arrays (GNRFETs). The nanoribbons serve as a channel for the transistors and are fabricated with a process based on e-beam lithography and dry etching of high mobility hydrogen intercalated epitaxial graphene. The widths of the nanoribbons vary from 50 to 20 nm, less than half those measured in previous reports for GNRFETs. Hall measurements reveal that the devices are p-doped, with mobility on the order of 2300 cm²/Vs. From DC characteristics, we find that the maximum ratio IMAX/IMIN is 5 obtained at 50 nm ribbons width. The IV characteristics of the GNRFETs are slightly non-linear at high bias without a full saturation. Therefore, despite the aggressive scaling of the graphene nanoribbon width, a bandgap is still not observed in our measurements. The high frequency performances of our GNRFETs are already significant at low bias. At 300 mV drain source voltage, the highest intrinsic (extrinsic) cut-off frequency ft reaches 82 (18) GHz and the extrinsic maximum oscillation frequency fmax is 20 GHz, which is promising for low power applications. [ABSTRACT FROM AUTHOR]

The cyclic olefin copolymer is a dielectric material with very attractive mechanical and electrical properties for millimeter- and submillimeter-based devices as recently demonstrated in a few applications. Here, we present the possibility of employing this material as a substrate for traveling-wave antennas through the design, fabrication, and characterization of a Yagi-Uda antenna working around 300 GHz. The developed fabrication process can be scaled to higher frequencies to take advantage of the extremely low absorption of such a dielectric at terahertz (THz) frequencies. The measurements agree well with the calculations, and a high gain of 15.4 dB has been achieved at 300 GHz. The measured bandwidth for a reflection coefficient of 10 dB is 10 GHz, and the radiation pattern presents a symmetrical main lobe with an angular width below 25° . [ABSTRACT FROM AUTHOR]

In this paper, we present a first full set of characteristics (dc, fT, fmax, and noise) of InAs/AlSb high-electron mobility transistors (HEMTs) operating under cryogenic temperature and low-power conditions. Those results are systematically compared and deeply analyzed at room temperature and 77 K. The characteristics improvement achieved at 77 K open up the possibility to develop ultralow-power cryogenic electronics (low-noise amplifier), featuring excellent high-frequency/noise performances below 100-mV dc biasing. [ABSTRACT FROM AUTHOR]

A D-Band power source implemented in the STMicroelectronics BiCMOS 55 nm technology and dedicated to on wafer characterization in millimeter-wave band frequency is presented. The circuit consists in multiplying by four a low frequency signal by cascading two frequency doublers. Two intermediate power amplifiers optimized at the second and fourth harmonics respectively are implemented after each doubler. A high-pass filter implemented before the second amplifier performs the rejection of the first and second harmonics to obtain a pure fourth harmonic output frequency. The measured peak output power is 10 dBm at 140 GHz with a −3 dB bandwidth of 24 GHz and a DC power consumption of 0.61 W. The total chip area is $1.7 \times 1.35$ mm2. [ABSTRACT FROM PUBLISHER]

In this paper, for the first time, we present a detailed RF experimental and simulation study of a 3-D multichannel SOI MOSFET (MCFET). Being different from the conventional planar technology, the MCFET features a total of three self-aligned TiN/HfO2 gate stacks fabricated on top of each other, allowing current to flow through the three undoped ultrathinned bodies (UTBs). In other words, the operation of the MCFET theoretically based on two UTB double-gate SOIs and a single-gate UTB fully depleted SOI (FDSOI) at the bottom. Using on-wafer S-parameters, the RF/analog figures-of-merit of an MCFET a gate length of 50 nm are extracted and discussed. Thanks enormous transconductance (gm) and very low output conductance, the RF/analog performances of MCFET-voltage gain (AVI) and early voltage (VEA) are superior compared with that single-gate UTB-FDSOI. However, these advantages diminish in terms of transition frequency (fT), due to the large total input gate capacitances (CGG). This inspires the introduction of spacer engineering in MCFET, aiming at improving both CGG and fT. The sensitivity of the spacer length to the RF/analog performances is experimentally analyzed, and the performance optimization is validated using ac simulation. This paper concludes that optimized MCFETs are a serious contender to the mainstream MOSFETs including FinFETs for realizing future low-power analog applications. [ABSTRACT FROM AUTHOR]

Abstract-Measurement and modeling procedures to accurately extract a small-signal equivalent circuit of advanced MOSFETs up to 220 GHz are proposed. The methodology carried out goes from the vector network analyzer calibration to the simulation results using complex deembedding. Good comparisons between the measurement and the simulation data obtained using this procedure are shown up to 220 GHz. [ABSTRACT FROM AUTHOR]

In this paper, the high-frequency properties of MOSFETs at low-temperature operation are investigated through measurements and electrical simulations. The experimental results show that the device achieves a 335-GHz ƒmax and a 300-GHz ƒt when operating at low temperature (78 K), which constitutes, respectively, a 78% and 34% improvement compared to the room temperature performances (296 K). The minimum noise figure NFmin decreases from 1.4 dB (296 K) to 0.5 dB at 30 GHz (78 K), while the associated gain increases from 8 to 12 dB. [ABSTRACT FROM AUTHOR]

This paper describes a 230-GHz self-aligned SiGeC heterojunction bipolar transistor developed for a 90.nm BiCMOS technology. The technical choices such as the selective epitaxial growth of the base and the use of an arsenic-doped monocrystalline emitter are presented and discussed with respect to BiCMOS performance objectives and integration constraints. DC and high-frequency device performances at room and cryogenic temperatures are given. HICUM model agreement with the measurements is also discussed. Finally, building blocks with state-of-the-art performances for a CMOS compatible technology are presented: A ring oscillator with a minimum stage delay of 4.4 ps and a 40-GHz low-noise amplifier with a noise figure of 3.9 dB and an associated gain of 9.2 dB were fabricated. [ABSTRACT FROM AUTHOR]

SiGe HBT noise parameters (NF\min, Rn and \Gammaopt) are for the first time extracted in the entire 130 – 170 GHz frequency range. This achievement is realized using a D-band on-chip source-pull system, which includes an impedance tuner integrated with the transistor under test. On-wafer noise power measurements on this system were performed for each tuner impedance state, from which are extracted the transistor noise parameters in the complete D-band. [ABSTRACT FROM PUBLISHER]

This letter provides an experimental demonstration of high-performance industrial MOSFETs thinned down to 5.7 \mu\m and transferred onto a 125- \mu\m-thick polyethylene naphthalate foil. The die stack transferred onto the organic substrate comprises the 200-nm-thick active layer and the 5.5- \mu\m-thick interconnection multilayer stack resulting in a light, compact, and bendable thin film. We unveil that dc and RF performances are invariant even for ultimate thinning down to the buried oxide layer. Furthermore, n-MOSFET performance is improved by \1.5\times compared with previous work, and the first demonstration of 100-GHz p-MOSFETs on an organic substrate is presented. Unity-current-gain cutoff and maximum oscillation frequencies as high as 150/160 GHz for n-MOSFETs and 100/130 GHz for p-MOSFETs on a plastic substrate have been measured, respectively. [ABSTRACT FROM PUBLISHER]