SiGe Technology Research Articles

Design and performance of bilateral interdigital coplanar waveguide phase shifter for rf communication applications

A new design of a bilateral interdigital coplanar waveguide (BI-CPW) phase shifter using tunable barium strontium titanate thin film is presented and analyzed. This new design has shown a phase shift of 203°/cm at 25 GHz. Compared to a normal coplanar waveguide (CPW) type, a two-thirds size BI-CPW phase shifter is realized by interdigital capacitive loading. The phase shifter is fabricated with processes fully compatible with current SiGe technology. In addition, it is shown that operating voltages can be reduced significantly within a practical range by the inclusion of a polysilicon layer as a control electrode.

AC performance of nanoelectronics: towards a ballistic THz nanotube transistor

We present phenomenological predictions for the cutoff frequency of carbon nanotube transistors. We also present predictions of the effects parasitic capacitances on AC nanotube transistor performance. The influence of quantum capacitance, kinetic inductance, and ballistic transport on the high-frequency properties of nanotube transistors is analyzed. We discuss the challenges of impedance matching for ac nano-electronics in general, and show how integrated nanosystems can solve this challenge. Our calculations show that carbon nano-electronics may be faster than conventional Si, SiGe, GaAs, or InP semiconductor technologies. We predict a cutoff frequency of 80 GHz/ L, where L is the gate length in microns, opening up the possibility of a ballistic THz nanotube transistor.

SiGe HMODFET “KAIST” Micropower Model and Amplifier Realization

The recently published small-signal KAIST model is used successfully to fit the measured RF characteristics of a novel SiGe n-HMODFET device operating at micropower levels and extracted small-signal model parameters for this device under micropower operation are presented here for the first time. This model is then used to predict the performance of a simple micropower amplifier (sub 300-/spl mu/W total power consumption), realized in SiGe technology, and a comparison of modeled versus measured data is included.

Comparison of sub-micron Si:SiGe heterojunction nFETs to Si nMOSFET in present-day technologies

The measured performance of sub-micron Si:SiGe Schottky gated HFETs is compared to Si nMOSFETs. To allow an up-to-date comparison between Si and strained-Si FETs, the different device types have been studied in their respective technologies. RF performance as given by the cut-off and maximum oscillation frequency is given as a function of input power. The evaluation highlights the current immaturity of the Si:SiGe technologies, where an average HFET shows a maximum transconductance of ∼300 mS/mm and cut-off frequency ∼60 GHz, while the new generation Si nMOS is reaching 1300 mS/mm and 120 GHz respectively. The comparison shows that the strength of the HFETs lies in low power operation (<200 μW).

Ultracompact SOI CMOS frequency doubler for low power applications at 26.5-28.5 GHz

In this paper, a complementary metal oxide semiconductor (CMOS) frequency doubler for wireless applications at Ka-band is presented. The microwave monolithic integrated circuit (MMIC) is fabricated using digital 90 nm silicon on insulator (SOI) technology. All impedance matching, filter and bias elements are implemented on the chip, which has a very compact size of 0.37 mm/spl times/0.27 mm. At an output frequency of 27 GHz, source/load impedances of 50 /spl Omega/, a supply voltage of 1.25 V, a supply current of 8 mA and an input power of -4.5 dBm, a conversion gain of 1.5 dB was measured. To the knowledge of the authors, the circuit has by far the highest operation frequency for a CMOS frequency multiplier reported to date and requires lower supply power than circuits using leading edge III/V and silicon germanium (SiGe) technologies.

MEMS SiGe Technologies for RF and Millimeterwave Communications

AbstractThis paper shows the potentialities of merging the MEMS and micromachining with SiGe technologies in order to speed up the performances of next generation of front end in term of flexibility, reconfigurability and adaptability. MEMS technologies are presented based on Benzo-Cyclo-Butene (BCB) materials and Bulk Acoustic Wave (BAW) materials. Special attention is paid to ensure a full compatibility between IC and MEMS. We have shown that very innovative functions could be considered by using this MEMSIC concept.

An 8-Bit 2-Gsample/s Folding-Interpolating Analog-to-Digital Converter in SiGe Technology

This paper deals with the design and implementation of an 8-bit 2-Gsample/s folding-interpolating analog-to-digital converter (ADC) using a SiGe technology with a unity gain cutoff frequency f/sub T/ of 47 GHz. The high-speed high-resolution ADC has applications in direct IF sampling receivers for wideband communication systems. The converter occupies an area of 3.5 mm/spl times/3.5 mm including pads and exhibits an effective resolution bandwidth of 700 MHz at a sampling rate of 2 Gsample/s. The maximum DNL and INL are 0.5 and 1 LSB, respectively. The ADC dissipates 3.5W (including output buffers) from a 3.3-V power supply.

Blooming of SiGe technology

Blooming of SiGe technology

Optimizing SiGe HBTs technology using small-signal and high frequency noise device's modeling

ABSTRACTThe rapid expansion of SiGe technologies during the last decade essentially due to civil telecommunication's applications have led Si/SiGe based heterojunction bipolar transistors (HBTs) to excellent performance levels, allowing high frequency low noise circuit designs such as linear low noise amplifiers( RF noise) or also low-phase noise oscillators (LF noise). Among these technologies, the SiGe BiCMOS one integrates digital and RF functions on the same chip. Fast improvements of the technological process have been performed thanks to large efforts allowed to characterization and modeling of the devices. We have investigated on the influence of technological parameters such as Germanium profile, doping level and thickness of the base layer (5 different wafers) on the dynamic and high frequency noise performances to converge towards the optimum technological process (now available with the BiCMOS6G processed by ST microelectronics). We made use of scattering parameters [S] measurements on the devices to extract the electrical parameters of our small signal model. The high frequency noise parameters based on the electrical model (with noise sources added to the junction, resistances) are simulated and compared with the measured noise parameters of the devices. The four noise parameters (Fmin, Rn, and complex Γopt) measurements have been performed from 1 GHz to 12 GHz, and the dynamic S parameters measurements have been realized in the 40 MHz-40 GHz range. These models have been used to enable the identification of the limiting parameters on the dynamic performances and on the high frequency noise parameters.

A 40-43-Gb/s clock and data recovery IC with integrated SFI-5 1:16 demultiplexer in SiGe technology

A fully integrated OC-768 clock and data recovery IC with SFI-5 1:16 demultiplexer is designed in a 120-GHz/100-GHz (f/sub T//f/sub MAX/) SiGe technology. The 16 2.5-Gb/s outputs and additional deskew channel are compliant with the Serdes Framer Implementation Agreement Level 5 specification. The measured bit-error rate is <10/sup -15/. The measured jitter tolerance exceeds the mask specified in G.8251. The IC operates with 1.8-V and -5.2-V supplies and dissipates 7.5 W.

Low-cost circuit solutions for micro- and millimeter-wave systems using commercially available SiGe technologies

Increased use of wireless technologies for communications and sensing results in spectral overcrowding in the lower GHz range. Spectrum allocations in the upper microwave and in the millimeter-wave ranges are available, yet realizing low-cost circuits, e.g. for the 24 GHz ISM band remains a challenge. We are investigating the use of two Si/SiGe hetero-junction bipolar transistor technologies at Atmel Germany (the commercially available SiGe1 and the emerging SiGe2 processes), combined with compact circuit design and back-end micromachining techniques, for the realization of cost-efficient RF frontend solutions at frequencies above 20 GHz. Results presented here include a fully monolithic receiver IC for 24 GHz, and a 33 GHz oscillator module combined with a thin-film antenna structure using wafer-level integration.

SiGe differential transimpedance amplifier with 50-GHz bandwidth

InP and SiGe technologies are both attractive for design of circuits operating at 40 GB/s and beyond. In this paper, we describe a fully differential SiGe transimpedance amplifier (TIA) suitable for differential phase-shift keying applications. The TIA exhibits 49 dB-/spl Omega/ transimpedance, greater than 50-GHz bandwidth, and input-referred current noise less than 30 pA//spl radic/Hz. For comparison, we have also developed a similar TIA in an InP double-heterostructure bipolar transistor technology. The InP TIA had 48 dB-/spl Omega/ transimpedance and 49-GHz bandwidth.

SiGe BiCMOS integrated circuits for high-speed serial communication links

Considerable progress has been made in integrating multi-Gb/s functions into silicon chips for data- and telecommunication applications. This paper reviews the key requirements for implementing such functions in monolithic form and describes their implementation in the IBM SiGe BiCMOS technology. Aspects focused on are the integration of 10-13-Gb/s serializer/deserializer chips with subpicosecond jitter performance, the realization of 40-56-Gb/s multiplexer/demultiplexer functions and clock-and-data- recovery/clock-multiplier units, and, finally, the implementation of some analog front-end building blocks such as limiting amplifiers and electro-absorption modulator drivers. Highlighted in this paper are the key challenges in mixed-signal and analog integrated circuit design at such ultrahigh data rates, and the solutions which leverage high-speed and microwave design and broadband SiGe technologies.

100 GHz dynamic frequency divider in SiGe bipolar technology

A 100 GHz dynamic frequency divider and a 62 GHz static frequency divider are presented, both using a -3.8 V supply and designed in IBM's 0.12 /spl mu/m SiGe technology with f/sub T/ of 207 GHz and f/sub MAX/ of 285 GHz. Static divider performance is compared to three other static dividers designed in IBM's 0.18 /spl mu/m SiGe BiCMOS technology.

A 14-bit Current-Steering DAC with Current-Mode Deglitcher

A 14-bit current-steering DAC utilizing parallel current memories operating as a deglitcher is presented. The high linearity of the current memories is based on a memory MOS transistor biased in the triode region and a bootstrapped sampling switch. The prototype circuit is implemented using a 0.35-μm BiCMOS (SiGe) technology and it occupies 5.7 mm2 of silicon area. According to measurements, THD is −66.8 dBc with a 9.1-MHz input signal and 30-MHz clock frequency. Two-tone test gives intermodulation levels below 68 dBFS at 40-MS/s sampling rate. The power dissipation is 370 mW from a 3-V supply.

A SiGe MMIC 6-bit PIN diode phase shifter

A 6-bit PIN diode phase shifter has been successfully demonstrated at microwave frequencies in a SiGe bipolar technology. A post-silicon polymer dielectric interconnect technology is implemented to achieve low loss microstrip structures on the silicon substrate. The monolithic microwave integrated circuit exhibits flat phase shift, low VSWR, and low insertion loss variation, over the 7- to 11-GHz band. This phase shifter demonstrates the feasibility of integrating SiGe technology into microwave systems.

Proton response of low-frequency noise in 0.20 μm 90 GHz fT UHV/CVD SiGe HBTs

The influence of proton exposure on the low-frequency noise of 0.20 μm UHV/CVD SiGe HBTs is presented. The noise degradation after irradiation shows a strong dependence on transistor geometry. Our previously developed noise theory is used to understand this behavior, and a comparison is made between these new results on third generation SiGe technology and our prior results on the first generation SiGe technology.

Silicon germanium heterojunction bipolar transistor electrostatic discharge power clamps and the Johnson Limit in RF BICMOS SiGe technology

Achieving radio frequency (RF) performance circuit objectives and electrostatic discharge (ESD) protection will continue to challenge future technology. In this study, we use the ultimate limitation of the transistor (known as the Johnson Limit) as a means to provide an ESD power clamp by utilizing a first low breakdown trigger device and a second high breakdown clamp device. Using the inverse relationship between unity current gain cutoff frequency and breakdown voltage, ESD power clamps are constructed using epitaxial base pseudomorphic silicon germanium (SiGe) heterojunction bipolar transistors in a common-collector Darlington configuration. ESD experimental test results from human body model (HBM), machine model (MM) and transmission line pulse (TLP) testing demonstrate the scaling of ESD power clamps. Design studies of alternative implementations, resistor ballasting and different trigger transistors will be discussed. As a comparative analysis, the SiGe-based ESD power clamps will be compared to CMOS MOSFET-based ESD power clamps. A new dimensionless group is defined to quantify the relationship between the power-to-failure and the maximum power. Additionally, a future SiGe technology is shown to provide insight into the impact of technology scaling on future SiGe ESD power clamps.

Electrical properties of SiGe microstructures fabricated by C.V.D. and F.I.B. and their applications in detectors

This work presents a study of the electrical parameters of SiGe heterostructures fabricated by low-pressure chemical vapour deposition. Results of the electrical resistance and Hall coefficient measurements of strained/Si heterostructures in the temperature range 77–300 K are reported. The study of the electrical parameter behaviour is based on the strain as well as degeneracy effects. Spreading resistance measurements of Si 1− x Ge x microstructures fabricated by focused ion beam–liquid metal ion sources techniques are reported. A schematic diagram of an infrared detector is also included for the application of SiGe technology.

Pre-Power Amplifier for 5.2 - 5.8 GHz Band

The design of a low-voltage and broadband pre-power amplifier for 5.2 GHz-5.8 GHz band is presented. The purpose of the pre-power amplifier is to separate the external power amplifier and internal mixer to deliver the required input power to the power amplifier. The amplifier is designed in 0.35 \um. SiGe technology. Differential topology is used in order to reduce the effect of the bonding inductances. The amplifier is optimized for maximum yield. The simulation results of the amplifier show 0 dBm output power with 13 dB gain. The gain variation is less than 0.5 dB in band.