III–V compound semiconductors, such as InGaAs/InAlAs, exhibit exceptional carrier transport properties, establishing them as fundamental elements in terahertz (THz) applications crucial for the development of 6G networks. These materials present the potential for high-performance, energy-efficient THz devices. Furthermore, their compatibility with heterojunction integration, particularly in hetero-integration with silicon-germanium (SiGe) bipolar complementary metal–oxide–semiconductor (BiCMOS), paves the way for cutting-edge THz devices. This advantage highlights the crucial role of III–V semiconductors in driving THz and 6G technology, meeting the evolving demands of future wireless communication and sensing systems. NSR conducted an interview with Dr. Dae-Hyun Kim, a semiconductor expert with a distinguished academic and professional background. Dr. Kim embarked on his career at Teledyne Scientific Company in 2008, later joining SEMATECH in 2012, where he played a crucial role in propelling semiconductor technology forward. In 2015, he assumed the position of an Associate Professor at Kyungpook National University. Dr. Kim's journey embodies his long commitment to the field, underscored by his remarkable contributions. In this interview, Dr. Kim shared his insights on fostering collaboration within the semiconductor field. He particularly emphasized on effective approaches for advancing research and innovation in semiconductor technology.

This paper presents a millimeter-wave low-pass filter to investigate the RF performance of passive structures in a lab-level thin metal micro-nano processing technology. It consists of 3-stage periodic stepped-impedance cell to have a slow-wave structure to offer a high attenuation of stop band with a compact size. The total size of the chip is less than 1.1 mm 2 . It achieves an insertion loss of less than 2 dB at a frequency range from 0 to 110 GHz with a measured cut-off frequency around 40 GHz. A rejection of higher than 20 dB is measured in a stopband from 52 to 110 GHz, which is larger than 2 times of fundamental frequency. The measurement agrees well with the simulation results. It shows the potential of RF passives in a lab-level thinner metal thickness technology towards monolithic microwave integrated circuits.

Recently, hafnium oxide based ferroelectric memories gained great attention due to good scalability, high speed operation, and low power consumption. In contrast to the FRAM concept, the FeFET offers non-destructive read-out. However, the integration of the FeFET into an established CMOS technology entails several challenges. Herein, an 1T1C FeFET with separated transistor (1T) and ferroelectric capacitor (1C) is described and demonstrated. This alternative approach can be integrated into standard process technologies without introducing significant modifications of the front-end-of-line. All important steps starting from the integration of MFM devices into the BEoL through the fabrication and characterization of single 1T1C memory cells with various capacitor area ratios for bit cell tuning up to the initial demonstration of an 8 kbit test-array are covered.

In our work we describe and demonstrate an alternative approach of integrating 1T-1C FeFET having separated transistor (1T) without modifying frontend CMOS technology and an additional gate-coupled ferroelectric (FE) capacitor (1C) embedded in the interconnect layers. Starting from the results of FE capacitor integration and 1T-1C single cell characterization this paper describes realization and results of a fully integrated 8 kbit memory array implementation.

In this paper, we present a broadband microwave characterization of ferroelectric hafnium zirconium oxide (Hf0.5Zr0.5O2) metal–ferroelectric–metal (MFM) thin film varactor from 1 kHz up to 0.11 THz. The varactor is integrated into the back-end-of-line (BEoL) of 180 nm CMOS technology as a shunting capacitor for the coplanar waveguide (CPW) transmission line. At low frequencies, the varactor shows a slight imprint behavior, with a maximum tunability of 15% after the wake-up. In the radio- and mmWave frequency range, the varactor’s maximum tunability decreases slightly from 13% at 30 MHz to 10% at 110 GHz. Ferroelectric varactors were known for their frequency-independent, linear tunability as well as low loss. However, this potential was never fully realized due to limitations in integration. Here, we show that ferroelectric HfO2 thin films with good back-end-of-line compatibility support very large scale integration. This opens up a broad range of possible applications in the mmWave and THz frequency range such as 6G communications, imaging radar, or THz imaging.

Dielectric spectroscopy in the sub-THz regime is a promising candidate for microfluidic-based analysis of biological cells and bio-molecules, since multiple vibrational and rotational transition energy levels exist in this frequency range (P. Siegel, “Terahertz technology in biology and medicine,” IEEE Trans. Microw. Theor. Tech., vol. 52, pp. 2438–2447, 2004). This article presents our recent efforts in the implementation of microfluidic channel networks with silicon-based technologies to unleash the potential of an integrated sub-THz microfluidic sensor platform. Various aspects of dielectric sensors, readout systems, flowmeter design as well as implemention- and technology-related questions are addressed. Three dielectric sensor systems are presented operating at 240 GHz realizing transmission-based, reflection-based and full two-port architectures. Furthermore different silicon based microchannel integration techniques are discussed as well as a novel copper pillar-based PCB microchannel method is proposed and successfully demonstrated.

The following study employs RF waveform engineering to monitor degradation in 22nm FDSOI transistor at high-frequency region. The current and voltage waveforms are measured, reconstructed, and de-embedded to the device’s intrinsic during large-signal CW RF stress testing. This technique provides extra information on device performance compared with standard DC and RF figures of Merits degradation. With clear pictures of where on the output IV plane the degradation is occurring, device designers can get an insight into the degradation behavior limiting RF performance. It is observed that devices show a different behavior under RF stress in comparison to DC-stress-induced degradation.

This paper presents a highly linear 79 GHz differential low-noise amplifier (LNA) for civil-automotive radars operating at the predefined frequency range from 77 GHz to 81 GHz. The circuit is optimized for frequency-modulated continuous-wave (FMCW) radar application, which typically require a very high input-referred 1 dB-compression point (iP 1dB ). A reconfigurable differential common-source stage with capacitive neutralization is employed together with a common-gate stage in cascode configuration as the core of the LNA. The performance of the circuit can be easily adjusted within the gain-NF-P 1dB trade-off boundaries by changing the voltage at the back-gate terminal of the common-source stage, thus tailored to the application specific requirements. Passive baluns are placed at input and output to characterize the differential circuit with the available single-ended laboratory instrumentation. The LNA is implemented in a 22 nm FD-SOI CMOS technology. Its core is very compact with an area of 0.04 mm 2 . The fabricated chip is experimentally characterized in the lab, and it shows a peak gain of 8.7 dB at 80 GHz. From 75 GHz to 85 GHz, the measured input referred P 1dB (iP 1dB ) is about -6 dBm, and the minimum noise figure (NF) is 5 dB. Compared with the state-of-the-art for LNAs operating in a similar frequency range, the presented circuit shows the highest iP 1dB and has the most compact circuit core, together with an excellent NF and a moderate gain, resulting in the best figure-of-merit.

A microwave characterization at UHF band of a ferroelectric hafnium zirconium oxide metal-ferroelectric-metal (MFM) capacitors for varactor applications has been performed. By using an impedance reflectivity method, a complex dielectric permittivity was obtained at frequencies up to 500 MHz. Ferroelectric Hf0.5Zr0.5O2 of 10 nm thickness has demonstrated a stable permittivity switching in the whole frequency range. A constant increase of the calculated dielectric loss is observed, which is shown to be an effect of electric field distribution on highly resistive titanium nitride (TiN) thin film electrodes. The C-V characteristics of a “butterfly” shape was also extracted, where the varactors exhibited a reduction of capacitance tunability from 18.6% at 10 MHz to 15.4% at 500 MHz.

In this article, we present the capacitance–voltage ( C – V ) characteristics of Hfx Zr1−x O2 metal–ferroelectric–metal (MFM) thin-film capacitors with various Zr doping, thicknesses, and annealing temperatures. The influence of doping, electric field cycling, and annealing temperature on tuning characteristics (tunability) was analyzed and an optimized bias region for the maximum tunability was defined. Additional focus was made on an antiferroelectric-like (AFE) behavior, which occurs for > 50% Zr doping. The presence of both the ferroelectric and the AFE phase manifests itself in specific C – V behavior, where a reduced bias range is required for tuning, however, at the cost of a smaller tunability. The suitability of this behavior for varactor applications is also discussed.

This paper presents a reflectometer with an integrated transducer as a high-integration miniaturized sensor for dielectric spectroscopy at 240 GHz in SiGe BiCMOS technology. The reflectometer consists of a signal generation component using 240-GHz multiplier chains, side-coupled directive couplers and a two-channel heterodyne receiver. Readout of the transducer upon exposure to liquids is performed by the measurement of its reflected signal using an external excitation source. The experimental dielectric sensing is demonstrated by using a binary methanol-ethanol mixture placed on the proposed on-chip dielectric sensor in the assembled printed circuit board.

This article presents a reflectometer-based on-chip dielectric sensor with integrated transducers at 240 GHz. The chip simplifies the measurement of a vector network analyzer (VNA) to sense the incident and reflected waves by using two heterodyne mixer-based receivers with a dielectric sensing element. Radio frequency (RF) and local oscillator (LO) submillimeter waves are generated by two frequency multiplier chains, respectively. Two back-to-back identical differential side-coupled directive couplers are proposed to separate the incident and reflected signals and couple them to mixers. Both transmission line and coplanar stripline transducers are proposed and integrated with reflectometer to investigate the sensitivity of dielectric sensors. The latter leads to a larger power variation of the reflectometer by providing more sufficient operating bands for the magnitude and phase slope of S11 . The readout of the transducers upon exposure to liquids is performed by the measurement of their reflected signals using two external excitation sources. The experimental dielectric sensing is demonstrated by using binary methanol–ethanol mixture placed on the proposed on-chip dielectric sensor in the assembled printed circuit board. It enables a maximum 8 dB of the power difference between the incident and reflected channels on the measurement of liquid solvents. Both chips occupy an area of 4.03 mm 2 and consume 560 mW. Along with a wide operational frequency range from 200 to 240 GHz, this simplified one-port-VNA-based on-chip device makes it feasible for the use of handle product and suitable for the submillimeter-wave dielectric spectroscopy applications.

A 480-GHz sensor consists of signal stimulus and the transducer element as well as a subharmonic mixer in a 130-nm SiGe BiCMOS technology is reported. It features a mixer-first architecture based on down-conversion subharmonic mixer, an local oscillator (LO) chain at 240-GHz using a frequency doubler with variable-gain characterization, and a 480-GHz RF chain, making the fully integrated 480-GHz receiver possible. In a frequency range of 210–270 GHz at a maximum of 1.5-V supply offset, the LO chain has a 14-dB power-level variation, comprising with a 120-GHz frequency quadrupler, a power amplifier, and a variable frequency doubler. The proposed subharmonic receiver is driven by the RF and LO chain with a multiplier factor of 16 and 8, respectively. In this way, 480-GHz signal is generated, fed through the transducer, and hetero-mixed at subharmonic mixer. The measured output power difference is adjustable over 8 dB. Along with the intermediate frequency (IF) bandwidth of 20 GHz, the wide RF bandwidth makes it suitable for submillimetre-wave receiver-based dielectric spectroscopy applications. The chip occupies an area of 2.2 mm 2 and consumes 290 mW.

The following study discusses the impact of hot-carrier degradation on high frequency performance of the 22nm FDSOI n-channel transistors. A quasi-static small-signal equivalent circuit MOSFET model is used to describe the device behavior. RF characteristics are extracted after stressing device with continuous DC. DC characteristics are also investigated thoroughly before and after stress. It is observed that, the device suffers from both interface damage and oxide defect. Accordingly, this study addresses how severe hot-carrier degradation affects the intrinsic parameters as well as the device performance.

This work gives an overview of integrated microwave to millimeter wave sensors and their applications covering frequencies from 28 GHz to 240 GHz. The designs are capable to address versatile application fields from liquid compound measurements to plaque detection and classification in arteries, glucose detection in continuous glucose monitoring (CGS) systems and virus detection in the context of respiratory diseases. The demonstrated approaches represent powerful and miniaturized solutions for highly sensitive contactless sensing of sample properties. Exploiting millimeter wave frequencies enables highest levels of integration to implement miniaturized sensing solutions including on-chip readout systems.

This paper presents the W-band noise performance of the 22nm FDSOI CMOS technology. In detail, the mm-wave thin-oxide MOSFETs is characterized comprehensively in term of device geometries using the tuner-based noise measurement approach. To aid the noise analysis and extraction, the following study adopts an accurate small-signal equivalent circuit model validated well with bias-dependence up to 110 GHz. The effects of back-gate bias to the overall noise performance are also addressed in this work. The test devices exhibit low noise figure in the full W-band 75-110 GHz. Besides, NF min of 2.8 dB and 3.6 dB is recorded at 94 GHz respectively for the n- and p-FETs with 18nm gate-length (N f = 32, W f = 1.0 µm). The result of this study indicates the comparable performance of the 22nm FDSOI technology to other candidates for W-band applications.

This paper presents a wideband integrated dielectric sensor with read-out circuit at 207-257 GHz in SiGe BiCMOS technology. The sensing element is equipped by a resonator that provides a bandpass frequency response which is varied in accordance to the carried permittivity change of the device under test. This variation can be sensed and recorded as the change of output voltage of an integrated 207-257 GHz 2 port vector network analyzer readout circuit. The demonstration of aforementioned readout system is verified by measuring the output of mixers as the reference, reflected and measured channel, and the uncalibrated S parameters of readout with different samples.

This article presents a fully differential power-tuning heterodyne on-chip sensing readout system at 240 GHz. The chip enables the measurement of not only the transmission parameter but also the reflection parameter to sense the permittivity of different materials by using four heterodyne mixer-based receiving channels connected to a dielectric sensing element. To facilitate the operation and characterization, three frequency multiplier chains are included to generate the required two identical radio frequency (RF) and one local oscillator (LO) subterahertz signals. RF frequency multiplier chain is configured to enable a tunable power level of the RF signal by using a variable attenuator. A chip prototype using 130-nm silicon–germanium (SiGe) BiCMOS is implemented with a size of 11 mm 2 and dc power consumption of 2.7 W. The measured 10-dB bandwidth of 20.8% is achieved in a frequency range from 207 to 257 GHz with 14-dB measured power-tuning range. The transmission and reflection parameters’ measurements for copper and gummi show a differentiated value in terms of magnitude and phase, which demonstrates the sensing function of the proposed readout system.

This paper investigates the applicability of a thick-oxide transistor from the 22FDX® for 5G NR sub-6 GHz front-end modules. Characterization and evaluation of the GlobalFoundries's FDSOI n-MOSFET regarding RF front-end figure-of-merits, such as output power, efficiency and linearity are discussed. Load-pull measurements are performed to extract the optimal performance. The test transistor delivers saturation power of +5.0 dBm and more than 65% of PAE while maintaining flat transducer gain of 10.2 ± 0.2 dB across the targeted frequency range for a 1.5 V single-ended class AB operation. Besides, the low PAE roll-off in term of reducing supply voltage and the particular 60% PAE at 10 dB output back-off indicate that the DUTs are well suitable for envelope tracking applications. Additional reliability tests at strong compression levels are conducted from which low performance degradation over time is observed even at 9 dB output compression.

This work presents a detailed study on the high-frequency performance of 22FDX ® FDSOI for 5G front-end power amplifiers. The following report focuses on the S-parameters and large-signal figure-of-merits such as output power, gain and power-added efficiency for an insightful and correct assessment on the device capability. DC characteristics of the test transistors are firstly investigated to determine the optimum operating point. Small-signal characterization is performed up to 110 GHz using a state-of-the-art mm-Wave measurement setup. An overall MSG/MAG of 16 ± 4 dB is recorded in the frequency range 10 - 80 GHz. On the other hand, large-signal performance on non-50 Ohm impedance environment is evaluated thoroughly through vector-receiver load-pull measurement up to 24 GHz. The measured output power and efficiency indicate that the DUTs perform well in the sub-6 GHz band and even in K-band. The outstanding experimental results emphasize the applicability and suitability of the 22FDX ® FDSOI technology platform for 5G low-power transmitters.