SiGe Technology Research Articles

Millimeter-Wave and Terahertz Transceivers in SiGe BiCMOS Technologies

This invited paper reviews the progress of silicon–germanium (SiGe) bipolar-complementary metal–oxide–semiconductor (BiCMOS) technology-based integrated circuits (ICs) during the last two decades. Focus is set on various transceiver (TRX) realizations in the millimeter-wave range from 60 GHz and at terahertz (THz) frequencies above 300 GHz. This article discusses the development of SiGe technologies and ICs with the latter focusing on the commercially most important applications of radar and beyond 5G wireless communications. A variety of examples ranging from 77-GHz automotive radar to THz sensing as well as the beginnings of 60-GHz wireless communication up to THz chipsets for 100-Gb/s data transmission are recapitulated. This article closes with an outlook on emerging fields of research for future advancement of SiGe TRX performance.

The Radiation Effect on Low Noise Amplifier Implemented in the Space-Aerial–Terrestrial Integrated 5G Networks

This paper provides the details of a study on the effects of electron irradiation on two Low Noise Amplifiers (LNA), the Gallium-Arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) based and the Silicon-Germanium (SiGe) Heterojunction Bipolar Transistor (HBT)-based. Previous studies have shown that the properties of GaAs and SiGe HBT's are very tolerant of gamma, neutron, and proton irradiation without additional radiation hardening. Nowadays, commercials on the shelves (COTS) LNAs have been used in CubeSat space communication systems which may be connected to other communication networks for the implementation of the space-aerial- terrestrial integrated 5G network (SATIN) systems projects, for satellites, launched into Low and Medium Earth Orbits. Previous studies suggest that the electron radiation in space may degrade the LNAs' performance and might even lead to its failure. Located at the front end of the communication receiver system, this paper conducted such investigation to evaluate the performance under the radiation of the GaAs and SiGe LNAs considering the physics of the technology of each LNA, respectively. The results indicate that both SiGe and GaAs technologies are affected after electron irradiation. As a result, this degradation of the LNAs' performance affected the communications system performance of the inter-satellite radio link. After the assessment of the quality performance of the communication link at the system level, it has been found that the inter-satellite space link will be at risk under high space radiation dose and the link BER degrades proportionally to the radiation dose level.

30 GHz SiGe active inductor with voltage controlled Q

An active inductor (AI) based on a cascade gyrator for 30 GHz applications implemented with a 0.25 μm in SiGe technology is presented. The gyrator converts not only a key capacitor into an inductor, but also an added resistor, into a negative resistor. This gyrator-RC has its losses compensated by the negative resistor improving the active inductor Q factor. Changing the bias voltage and current allows to obtain a variable AI. A study of a cascade gyrator AI topology is done to understand the circuit behavior and key elements. For this purpose, an AI impedance model is introduced and discussed. An improved AI with the added resistor replaced by a voltage controlled mosfet resistor is proposed. This extra control voltage allows the variable AI quality factor fine tuning. Schematic and circuit extracted from layout simulations are presented, and compared with the measured results of two prototypes of the AIs (one with a fixed resistor and other with a voltage controlled resistor). A prototype of a high pass filter using the AI with fine Q control was fabricated. Non-linear simulations for different input signal levels were performed and compared with measurements. Also discussion on the non-linear models accuracy is performed.

Synthetic Transmission Lines in Cutoff Operation for Wideband High-Impedance DC Supplies

This brief describes a novel technique for the distribution of dc power based on synthetic transmission lines with a low cutoff frequency. Since after the cutoff the impedance of these lines approaches that of an open, these components are well suited to feed dc power in circuit nodes where high impedance values are required. Narrowband bias networks based on inductors or lambda-quarter (λ/4) stubs can be substituted by the presented wideband design solution. To experimentally validate the approach, two prototypes have been implemented in a 130 nm SiGe technology. The first prototype is a synthetic line with a cutoff frequency of 12 GHz, while the second design is a distributed amplifier (DA) where a synthetic line in cutoff feeds the voltage supply. Compared to traditional approaches based on inductors or λ/4 stubs, the presented technique improves the DA bandwidth by 50% and the flatness of the frequency response. Compared to biasing achieved via the DA termination resistor, the power-added-efficiency (PAE) is doubled. To the best knowledge of the authors, this is a novel general technique for feeding dc power to any circuit from a wideband high-impedance.

A 37–42-GHz 8 × 8 Phased-Array With 48–51-dBm EIRP, 64–QAM 30-Gb/s Data Rates, and EVM Analysis Versus Channel RMS Errors

This article presents a 5G 37–42-GHz $8\times 8$ phased array. The array is based on $2\times 2$ SiGe transmit/receive (TRX) beamformer chips in the SiGe technology with 6 bits of phase control and 8 bits of gain control. A detailed study is presented, showing the effects of array-level amplitude and phase errors on the radiated error vector magnitude (EVM) of 64-element arrays. The array scans to ±60° in the azimuth plane and ±50° in the elevation plane with low sidelobes. The measured peak effective isotropic radiated power (EIRP) is 51 dBm at Psat with a 3-dB bandwidth of 36–41.5 GHz. A 39-GHz communication system is also demonstrated along with a high-pass filter and an integrated upconverter/downconverter and achieves a local oscillator (LO) and image rejection level of 50 dBc, meeting FCC requirements of <−13 dBm/MHz of total leakage power. The array achieves < 5% EVM (−26 dB) using a 64-QAM 200-MHz waveform at an average EIRP of 44 dBm over all scan angles, including the LO and upconverter/downconverter contributions. A 30-Gb/s communication link with 64-QAM modulation is also shown. To our knowledge, this is the first demonstration of a 39-GHz phased-array communication system for 5G applications.

Design and Analysis of fT-Doubler-Based RF Amplifiers in SiGe HBT Technology

For performance-driven systems such as space-based applications, it is important to maximize the gain of radio-frequency amplifiers (RFAs) with a certain tolerance against radiation, temperature effects, and small form factor. In this work, we present a K-band, compact high-gain RFA using an fT-doubler topology in a silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs) technology platform. The through-silicon vias (TSVs), typically used for small-size chip packaging purposes, have been effectively utilized as an adjustable matching element for input impedance, reducing the overall area of the chip. The proposed RFA, fabricated in a modest 0.35 µm SiGe technology, achieves a gain of 14.1 dB at 20 GHz center frequency, and a noise figure (NF) of 11.2 dB at the same frequency, with a power consumption of 3.3 mW. The proposed design methodology can be used for achieving high gain, avoiding a complex multi-stage amplifier design approach.

Baseband to 140-GHz SiGe HBT and 100-GHz InP DHBT Broadband Triple-Stacked Distributed Amplifiers With Active Bias Terminations

This article describes the design and performance of a 140-GHz SiGe and a 100-GHz InP triple-stacked HBT distributed amplifier with active bias terminations. The active bias network is configured to extend the practical low-frequency operation while maintaining gain flatness and linearity. Triple-stacked HBTs are used to increase the gain-bandwidth and linear output capability. The SiGe design is based on HBTs with a peak f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> /f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> of 300/350 GHz and achieves 11.7 dB of gain and a bandwidth from baseband to 140 GHz. The InP HBT design is based on DHBTs with a peak f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> /f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> of 250/250 GHz and obtains a gain of 10.8 dB and a bandwidth of 100 GHz. Although the SiGe design achieves 1.5 times higher gain-bandwidth, the InP DHBT design achieves ~3-4.5 dB greater IP3, P1 dB, and P3 dB while consuming only ~23% higher dc power. These results represent the first broadband performance comparison of near-identical (apples-apples) DA designs implemented in SiGe and InP HBT device technologies. Although there are previous reports of larger bandwidth distributed amplifiers in both InP and SiGe technologies demonstrated up through 200 GHz, the InP and SiGe monolithic microwave integrated circuits (MMICs) described in this article are believed to represent the highest bandwidths reported for HBT DAs using practical on-chip active bias terminations.

A 130 GHz Fully-Integrated Fundamental-Frequency D-Band Transmitter Module With &gt; 4 dBm Single-Ended Output Power

A 130 GHz fully-integrated fundamental-frequency transmitter (TX) module with 4.4 dBm single-ended measured output power in a 130 nm SiGe technology is presented. The transmitter achieves in measurement a phase noise of −88 dBc/Hz at 1 MHz offset frequency from a 130 GHz carrier and a tuning range of 17 GHz. Its relatively compact size, low power consumption and high output power, enables the TX module to be integrated into more complex D-Band transceiver modules for radar and imaging applications. Due to the available measurement equipment, it was only possible to measure the output power single-ended. The measured single-ended output power is 4.4 dBm. This corresponds well to a simulated maximum differential output power of 8.1 dBm. To the best of the author’s knowledge, the presented chip exhibits one of the highest output power for fundamental-frequency TX modules among the recently reported state-of-the art chips in this frequency range.

STUDY OF A SOLAR CELL WITH A MULTILAYERED WINDOW BASED ON Si1-xGex USING AMPS-1D

The Silicon-Germanium (SiGe) technology, whose preliminary developments date from the mid-1980s and whose arrival on the market is recent, meets this joint need for economy and performance. In our days solar cells to thin films are increasingly used primarily because of their low cost. In recent decades the performance of these cells were significantly improved. In this work, we simulate solar cell base Si (1-x) Ge (X) multilayer window using software (AMPS-1D) to analyze some parameters. In particular, the properties of the window layer (thickness, doping, etc.) play a key role in the performance of the cell, and in order to optimize them, their influence on the photovoltaic quantities of the solar cell is studied. In order to highlight the importance of the deposition of a Si (1-x) Ge (X) type window layer on the Si (1-x) Ge (X) solar cells, a comparison between three cells , one with a window layer, the other with two layers windows and the third with three layers windows was made under 300 K and one sun (AM1.5) . The optimal solar cell was founding for the first window layer ( 100 nm ; x = 0.3 ) ,second window layer ( 80 nm ; x = 0.2 ) and the third window layer ( 60 nm ; x = 0.1 ) for 15.56 % optimal efficiency. This comparison led to the following conclusion: the multiplication of the cascade windows leads to a cell equivalent to a gradual window.

PERFORMANCE OF SIGE SOLAR CELL WITH BSF LAYER EFFECT OF TEMPERATURE AND WINDOW LAYER

The Silicon-Germanium (SiGe) technology, whose preliminary developments date from the mid-1980s and whose arrival on the market is recent, meets this joint need for economy and performance. In our days solar cells to thin films are increasingly used primarily because of their low cost. In recent decades the performance of these cells were significantly improved. In this work, we studied the temperature effect on performance forSiGe solar cell with BSF layer using software AMPS-1D to analyze some parameters. The temperature is one of most important effect and it plays a key on performance of solar cell.

10-GHz Fully Differential Sallen–Key Lowpass Biquad Filters in 55nm SiGe BiCMOS Technology

Multi-GHz lowpass filters are key components for many RF applications and are required for the implementation of integrated high-speed analog-to-digital and digital-to-analog converters and optical communication systems. In the last two decades, integrated filters in the Multi-GHz range have been implemented using III-V or SiGe technologies. In all cases in which the size of passive components is a concern, inductorless designs are preferred. Furthermore, due to the recent development of high-speed and high-resolution data converters, highly linear multi-GHz filters are required more and more. Classical open loop topologies are not able to achieve high linearity, and closed loop filters are preferred in all applications where linearity is a key requirement. In this work, we present a fully differential BiCMOS implementation of the classical Sallen Key filter, which is able to operate up to about 10 GHz by exploiting both the bipolar and MOS transistors of a commercial 55-nm BiCMOS technology. The layout of the biquad filter has been implemented, and the results of post-layout simulations are reported. The biquad stage exhibits excellent SFDR (64 dB) and dynamic range (about 50 dB) due to the closed loop operation, and good power efficiency (0.94 pW/Hz/pole) with respect to comparable active inductorless lowpass filters reported in the literature. Moreover, unlike other filters, it exploits the different active devices offered by commercial SiGe BiCMOS technologies. Parametric and Monte Carlo simulations are also included to assess the robustness of the proposed biquad filter against PVT and mismatch variations.

A Tunable SiGe BiCMOS Gain-Equalizer For X-Band Phased-Array RADAR Applications

This brief presents a compact-size tunable gain-equalizer for X-band phased-array RADAR applications in a 0.25- $ \mu \text{m}$ SiGe BiCMOS technology. An isolated nMOS-based variable resistance was used for the first time to tune the slope of the gain-equalizer. For nMOS, an isolated body created by a deep n-well was utilized to reduce insertion loss due to the substrate conductivity. Furthermore, the power-handling capability of the tunable gain-equalizer was improved thanks to the resistive body-floating technique. The designed tunable gain-equalizer operates in the frequency range from 8 to 12.5 GHz with a measured positive slope of 1 dB/GHz and 1 dB tunable slope. The effective chip area excluding the pads is 0.21 mm2, and the total area including pads is 0.31 mm2. To authors best knowledge, this brief is the first tunable gain-equalizer in SiGe technology presented for X-band phased-array RADAR applications.

Non-destructive techniques for evaluating the reliability of high frequency active devices

SiGe and GaN technologies have achieved rapid development over the last two decades. High level of RF circuit integration on Si low cost substrates open the way for large development of SiGe HBTs, while needs for high power density make GaN HEMT a key technology for solid state power modules. As both of these technologies achieve very elevated frequencies, they become strong contenders to GaAs technologies. Then reliability studies are needed to improve the process at the lower technology readiness level scale, and to stabilize the technological process till the final qualification step. To make an efficient diagnostic on the causal origin of the physical root mechanisms involved during the application of a stress, a multi-tool approach is mandatory to secure the diagnostic. In this paper, case studies on SiGe HBT and GaN HEMT stressed devices are proposed through the cross-analysis of low frequency noise spectral densities, of electrical transient measurements, and of TCAD simulations.

Ultra-Low Noise Amplifier for X-Band SiGe BiCMOS Phased Array Applications

This brief presents, a low noise amplifier (LNA) with sub-1dB noise figure (NF) at X-Band. Different than generally known noise-and-power match technique, the presented LNA is designed by considering impedance between the base-collector terminals of an HBT in common-emitter configuration. The presented amplifier stage can achieve sub-1 dB NF performance with ~10 dB gain. The LNA dissipates 19.8 mW of dc power and has 0.77 dB NF while occupying 0.4 mm2. It succeeds 1.5 dBm of input-referred compression point. To the best of authors’ knowledge, the presented work achieves the best NF performance in the literature of any LNA that utilizes SiGe technology.

Analysis of SRAM Enhancements Through Sense Amplifier Capacitive Offset Correction and Replica Self-Timing

An analysis of timing and input-referred offset of sense amplifiers (SA) is presented, and a new SA architecture with capacitive offset correction is proposed. Offset sources are first analyzed in a cross-coupled latch-based SA design, and the analysis is then extended to the proposed SA. The results show the proposed offset correction technique can reduce the total sensing time by up to 40%, while eliminating dynamic offset due to the difference in resolving inverters trip points. A self-timed SRAM with a new replica timing structure is designed to generate optimal SA enable timing with respect to the total input-referred offset. Calculations for timing delay and offset are compared with simulation results in both a conventional and a proposed SA design. The presented simulation results are based on a 10 Kb CMOS SRAM array in 130 nm BiCMOS SiGe technology operating at a 500 MHz clock and 1.5 V supply.

A 16-QAM 100-Gb/s 1-M Wireless Link With an EVM of 17% at 230 GHz in an SiGe Technology

This letter presents a 1-m wireless link established with a set of fundamentally operated Tx/Rx direct-conversion in-phase and quadrature (IQ) radio frequency (RF) front-end modules in a 0.13- $\mu \text{m}$ SiGe HBT technology featuring full chip-on-board packaging. Using a 16-quadrature amplitude modulation, data rates from 20 to 100 Gb/s with an error vector magnitude from 7% to 17% were achieved at a 1-m distance. Thanks to the new mixer-first Rx, the maximum data rate improved from 90 to 100 Gb/s compared with our previous work using the amplifier-first Rx. The peak performance was reached at 230 GHz. The Tx operates at a 3.5 dB backoff from $\text{P}_{\textbf {sat}}$ showing a 3-dB RF bandwidth (BW) of 28 GHz, a $\text{P}_{\textbf {out}}$ of 5 dBm, and an IQ imbalance below 0.7 dB. The Rx features a peak conversion gain of 8 dB, a single-sideband noise figure of 14 dB, a 3-dB RF BW of 26 GHz, and an IQ imbalance below 1 dB. This letter also provides an analysis of the RF front-end imperfections related to the large link BW.

Sub-1-dB and Wideband SiGe BiCMOS Low-Noise Amplifiers for &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$X$ &lt;/tex-math&gt; &lt;/inline-formula&gt;-Band Applications

In this paper, a design methodology for SiGe HBT-based low-noise amplifiers (LNAs) is proposed that can be utilized for both sub-1-dB noise figure (NF) and wide bandwidth as an alternative to the conventional simultaneous input noise and power matching technique. This paper focuses on the removal of the series base inductor and the inclusion of an output matching network as a design parameter that can be used to achieve both sub-1dB NF and wide bandwidth. The effects of the mentioned design parameters on NF and bandwidth are described and analyzed, including the comparison of results with the conventional design technique. To demonstrate the validity of the analysis and impact of utilizing base-to-collector capacitance on LNA performance metrics, two different LNAs implemented in a 0.13- $\mu \text{m}$ SiGe technology. The first LNA achieves a lower than 1-dB NF with 26-dB gain at 8.5 GHz, and the second LNA exhibits wideband operation, with a better than 10-dB return losses in the range of 8–35 GHz and lower than 3-dB NF from 6 to 20 GHz. The sub-1-dB LNA reaches −17.3 dBm of input-referred compression point (IP1dB), with a power consumption of 62 mW and an area of 0.795 mm2. The wideband LNA achieves 17.6 dB of peak gain with a 48.5-mW power consumption and 0.69-mm2 chip area. To the best of our knowledge, this paper achieves the best NF performance in the literature utilizing a SiGe technology, while the wideband LNA exhibits the best operational bandwidth, together with a reasonable low-noise performance.

32-GS/s 6-bit DAC based on SiGe technology for IM-DD OFDM systems with non-uniform quantization.

In this paper, we design and fabricate a 32-GS/s 6-bit digital-to-analog convertor (DAC) based on SiGe technology. The DAC uses double sampling technique and segment current steering architecture to achieve high dynamic linearity. A corrector circuit is proposed to suppress the duty cycle error for linearity optimization. The spurious free dynamic range (SFDR) is above 31.5 dBc over the Nyquist bandwidth at the sampling rate of 32-GS/s. A full-rate input interface is integrated to realize data exchange with field-programmable gate array (FPGA). The experimental results show that the net data rate of 50-Gb/s orthogonal frequency division multiplexing (OFDM) signals with non-uniform quantization can be generated by the designed and fabricated DAC. The OFDM signal transmission over 10-km standard single mode fiber (SSMF) with 64-quadrature amplitude modulation (QAM) and 128-QAM formats have been successfully achieved.

Broadband MMIC Digital Step Attenuator Based on Silicon-Germanium Technology

The article describes circuit schematics, features and design methodology of microwave integrated digital step attenuators (DSAs) based on SiGe technology (SiGe BiCMOS). The measured characteristics of the designed 0.1–4.5 GHz microwave monolithic integrated circuit (MMIC) DSA with a parallel and serial control driver are presented. The DSA bitness is 6 bit, attenuation range is 30 dB with a 1-dB step, and input power at the 1 dB gain compression is no less than 14 dBm. In addition to the wide bandwidth, advantages of the MMIC DSA are a good input and output matching, as well as low consumption current. The MMIC DSA can be used in microwave transmitters and receivers for different applications, including ones that are based on the systemon-a-chip concept.

The Effects of Temperature on the Single-Event Transient Response of a High-Voltage (&gt;30 V) Complementary SiGe-on-SOI Technology

The single-event transient response of a high-voltage complementary SiGe-on-silicon-on-insulator technology is investigated along with its temperature dependence using a pulse laser. The p-n-p silicon-germanium heterojunction bipolar transistor (SiGe HBT) shows a larger transient peak amplitude compared to the n-p-n SiGe HBT, which is largely related to the differences in total device volume and peak germanium content between the p-n-p and n-p-n devices. The effects of temperature on the transient response are also investigated using heaters and sensors mounted directly on the device-under-test package. The collector transient peak amplitude shows a negative temperature coefficient for a $V {_{\text {CB}}}$ of 0-V condition, for both the n-p-n and p-n-p devices. However, the temperature dependence of the transient peak amplitude becomes significantly weaker at $V {_{\text {CB}}}>0$ V. Calibrated TCAD simulations were performed to better understand the temperature dependence, and the simulations indicated that the electric field and mobility at higher $V {_{\text {CB}}}$ have a reduced temperature dependence than at a $V {_{\text {CB}}}$ of 0 V. The effects of self-heating are also explored using TCAD simulations and show that even under aggressive self-heating conditions, there is only less than 10% reduction in transient peak amplitude with the self-heating models turned on. The results shown suggest that this particular SiGe technology can be used for environments where highly energetic particles and high temperatures are encountered simultaneously.