A 6.5—16-GHz monolithic power amplifier module

A miniaturized 6.5-16-GHz power amplifier module, which includes T/R switch, dual polarity power supply, switch driver, and gate functions, was designed using two types of broad-band MMIC amplifiers. The two cascade designs were a 900-1200-µm FET amplifier and a 300-300-µm feedback amplifier which were used to provide large and small gain functions, respectively. The module exhibits 35 dB of gain, 1-W power output, and 55-dB T/R switch isolation.     

A high-yield, 3—7-GHz, 0.5-W push-pull GaAs MMIC amplifier

A high-yield, 3-7-GHz, 0.5-W MMIC GaAs amplifier has been successfully designed and tested. The amplifier features small chip size (1.2 mm sq.), high gain (12 ± 1.5 dB), high power-added efficiency (20 percent), good RF yield (57 percent, and high tolerance to process variations. Packaged amplifiers were built with this chip for both the 2-6-GHz and the 5.9-6.4-GHz bands. Saturated output power of 25 dBm was achieved in the 2-6-GHZ band, and 27 dBm in the 5.9-6.4-GHz band. Infrared measurements show that the device has low FET channel temperatures when operated at full bias power over the full range of military ambient temperatures.     

Design and process sensitivity of a two-stage 6—18-GHz monolithic feedback amplifier

The design of a 6-18-GHz two-stage monolithic feedback amplifier is discussed, and the critical process and FET parameters are identified. Variations in circuit performance experienced during a pilot production run are correlated with the predictions of a sensitivity analysis. Five circuit model parameters were selected for study: substrate height, GaAs sheet resistance, gate-source capacitance, transconductance, and drain-source resistance. Measured results show the importance of substrate height and sheet resistance in the control of gain flatness. An example on-slice RF performance distribution is presented, showing the suitability of the circuit and fabrication process for high-volume production.     

1—2-keV Boron implants into silicon

1000-Å-A thick heavily doped layers have been produced in Si by implanting B at energies as low as 1-2 keV. No preamorphization is required and the near-surface random peak is redistributed by diffusion into the deeper channeled region to provide sharp junctions. Doping levels of ∼ 2 × 10²⁰cm^-3can be maintained over a region ∼600-Å-thick while maintaining junction depths as shallow as 1000 Å.     

Mermaid—A front-end to distributed heterogeneous databases

Mermaid is a system that allows the user of multiple databases stored under various relational DBMSs running on different machines to manipulate the data using a common language, either ARIEL or SQL. It makes the complexity of this distributed, heterogeneous data processing transparent to the user. In this paper, we describe the architecture, system control, user interface, language and schema translation, query optimization, and network operation of the Mermaid system. Future research issues are also addressed.     

FT3—A metropolitan trunk lightwave system

FT3 is a 44.7 Mbit/s (DS3) digital lightwave transmission system intended primarily for metropolitan trunking. The system terminal includes a new multiplex, MX3, which provides interfaces for lower rate DS1, DS1C, or DS2 signals. The multiplex and lightwave line terminal are integrated into a single equipment configuration. Regenerators, containing laser transmitters and APD receivers, are spaced at approximately 4-mi intervals. A ribbon structured cable, containing up to 144 fibers, provides a maximum system capacity of about 40000 voice circuits. System parameters, maintenance, and performance features are consistent with requirements imposed by metropolitan digital trunk networks. The first fully standard application is planned for Atlanta, GA in December 1980, with several early follow-on applications already committed.     

A BiCMOS Ultra-Wideband 3.1–10.6-GHz Front-End

This paper presents a direct-conversion receiver for FCC-compliant ultra-wideband (UWB) Gaussian-shaped pulses that are transmitted in one of fourteen 500-MHz-wide channels within the 3.1–10.6-GHz band. The receiver is fabricated in 0.18-$mu$m SiGe BiCMOS. The packaged chip consists of an unmatched wideband low-noise amplifier (LNA), filter, phase-splitter, 5-GHz ISM band switchable notch filter, 3.1–10.6-GHz local oscillator (LO) amplifiers, mixers, and baseband channel-select filters/buffers. The required quadrature single-ended LO signals are generated externally. The average conversion gain and input$P_1 dB$are 32 dB and$-$41 dBm, respectively. The unmatched LNA provides a system noise figure of 3.3 to 5 dB over the entire band. The chip draws 30 mA from 1.8 V. To verify the unmatched LNA's performance in a complete system, wireless testing of the front-end embedded in a full receiver at 100 Mbps reveals a$10^-3$bit-error rate (BER) at$-$80 dBm sensitivity. The notch filter suppresses out-of-band interferers and reduces the effects of intermodulation products that appear in the baseband. BER improvements of an order of magnitude and greater are demonstrated with the filter.     

1 µm MOSFET VLSI technology: Part II—Device designs and characteristics for high-performance logic applications

Micrometer-dimension n-channel silicon-gate MOSFET's optimized for high-performance logic applications have been designed and characterized for both room-temperature and liquid-nitrogen-temperature operation. Appropriate choices of design parameters are shown to give proper device thresholds which are reasonably independent of channel length and width. Depletion-type devices are characterized at room temperature for load device use. Logic performance capability is demonstrated by test results on NOR circuits for representative fan-out and loading conditions. Unloaded ring oscillators achieved switching delays down to 240 ps at room temperature and down to 100 ps at liquid nitrogen temperature.     

Field-assisted semiconductor photoemitters for the 1—2-µm range

Photoemission data and model calculations are presented for a field-assisted semiconductor photoemitter which has achieved reflection-mode quantum efficiencies as high as 8.0 percent at 1.55 µm. The cathodes are p-p heterostructures employing lattice-matched InP-InGaAsP alloys. A thin electron semitransparent Schottky barrier provides the biasing contact for field-assisted electron emission. Parameters for optimal photoemission and sources of dark-current emission are discussed.     

1 µm MOSFET VLSI technology: Part VII—Metal silicide interconnection technology—A future perspective

A major limitation of polycrystalline silicon as a gate material for VLSI applications is its limited conductivity which restricts its usefulness as an interconnection level. An alternative approach which combines a doped polycrystalline silicon layer with a high-conductivity metal silicide such as WSi2(polycide) is described. Such polycide layers are demonstrated to provide at least an order of magnitude improvement in interconnection resistance relative to polycrystalline silicon while maintaining the reliability of the polycrystalline silicon gate and the ability to form passivating oxide layers under typical polycrystalline silicon processing conditions.     

A Space-Mapping Framework for Engineering Optimization—Theory and Implementation

This paper presents a comprehensive approach to engineering design optimization exploiting space mapping (SM). The algorithms employ input SM and a new generalization of implicit SM to minimize the misalignment between the coarse and fine models of the optimized object over a region of interest. Output SM ensures the matching of responses and first-order derivatives between the mapped coarse model and the fine model at the current iteration point in the optimization process. We provide theoretical results that show the importance of the explicit use of sensitivity information to the convergence properties of our family of algorithms. Our algorithm is demonstrated on the optimization of a microstrip bandpass filter, a bandpass filter with double-coupled resonators, and a seven-section impedance transformer. We describe the novel user-oriented software package SMF that implements the new family of SM optimization algorithms.     

A 12–18-GHz Three-Pole RF MEMS Tunable Filter

This paper presents a state-of-the-art RF microelectromechanical systems (MEMS) wide-band tunable filter designed for the 12–18-GHz frequency range. The coplanar-waveguide filter, fabricated on a glass substrate using loaded resonators with RF MEMS capacitive switches, results in a tuning range of 40% with very fine resolution, and return loss better than 10 dB for the whole tuning range. The relative bandwidth of the filter is$hbox5.7pm hbox0.4hbox%$over the tuning range and the size of the filter is 8 mm$, times ,4$mm. The insertion loss is 5.5 and 8.2 dB at 17.8 and 12.2 GHz, respectively, for a 2-$hboxkOmega/hboxsq$bias line. The loss improves to 4.5 and 6.8 dB at 17.8 and 12.2 GHz, respectively, if the bias line resistance is increased to 20$hboxkOmega/hboxsq$. The measured$ IIP_3$level is$≫$37 dBm for$Delta f ≫ 200$kHz. To our knowledge, this is the widest band planar tunable filter to date.     

γ—Radiation effects on MOSFET's fabricated with NMOS Submicrometer technology

In this letter, we report γ-radiation effects on MOSFET's fabricated with NMOS submicrometer technology. We have investigated the radiation sensitivity of n-channel MOSFET's with Leffvarying from 6 to 0.3 µm and with a gate oxide thickness of 250 Å. We observed that, for radiation doses ≤ 10⁴rad's, the threshold voltage shift is less than 75 mV and this shift is independent of the device geometry (even for Leff= 0.3 µm). A comparision has also been made between TaSi2gate MOSFET's and poly-gate MOSFET's. The deposition of TaSi2on poly/oxide/silicon structure does not decrease the radiation sensitivity of these MOSFET's. We have also compared MOSFET's fabricated with X-ray lithography and optical lithography. The X-ray lithography does not have a significant effect on the radiation sensitivity of these MOSFET's.     

An optimized π/2 distributed feedback laser

The effects of a periodicity interruption (phase slip) in distributed feedback lasers are investigated with attention given to the practical aspects of today's semiconductor lasers in the 1.5 μm region. We find that effects on gain threshold and mode discrimination should be large and favorable if the size and placement of a phase slip are correct.     

A Cr—Ag—Au metalization system

A comprehensive study of a Cr-Ag-Au metalization system, as well as a comparison with an aluminum system, is described. The Cr-Ag-Au metalization system, which can be deposited in a conventional evaporator with relatively little increase in processing complexity, has the desirable characteristics of aluminum metalization. It can be patterned more easily than equivalent thicknesses of aluminum. The Cr-Ag-Au has excellent storage characteristics at 300°C and has a much longer mean time to failure than does aluminum under high current density-high temperature stress. In addition, measurements show that with the use of an enhancement diffusion the Cr-Ag-Au produces as good as or better contact to p- and n-type silicon than does aluminum. Finally, the absence of significant metalization-oxide interaction makes Cr-Ag-Au useful for MOS devices and the ease with which contact is made between layers of this metalization indicates a number of applications for Cr-Ag-Au in multilayered devices.     

Seismic borehole tomography—Theory and computational methods

Tomographic inversion can be applied to seismic traveltime data to obtain a map of seismic velocities in a rock volume, although the field geometries will not, in general, allow a complete ray sampling. This paper deals with theoretical and computational aspects of tomographic inversion under such circumstances. It is shown that some usual measurement geometries could, in theory, be sufficient for determining the seismic velocity distribution uniquely (under the straight-ray approximation). From the computational point of view, however, the inverse problem can be poorly conditioned. The usual transform methods of reconstruction, developed for medical tomography, are not applicable. A brief discussion is, therefore, given of a few relevant geophysical inverse techniques and the CG-algorithm applied to a certain quadratic functional is shown to give reasonable images. A convergence result that contains "ART with smoothing" as a special case is also obtained. Techniques to correct for ray bending are discussed.     

Transmission line pulse transformers—Theory and applications

The advent of fast rise-time pulse techniques and their increasing importance brought on by high-speed microminiature circuits and the computer industry has resulted in an increased demand for pulse transformers of various types. The basic idea of constructing transmission line type transformers has been known and used for a number of years. However, such devices have not gained widespread usage, partly because their existence is not well known, but largely because of a lack of basic understanding of their operating principles in terms of elementary fundamentals as well as their capabilities and limitations. The purpose of this paper is twofold. One aim is to develop in step-by-step fashion the basic ideas of transmission line transformers from ordinary transmission line theory. The subject will be approached from the point of view of pulse response rather than ac excitation as is usually the case. Both impedance transformers and balanced-to-unbalanced (balun) transformers, including inverters, will be considered with physical insights into their operation. Several fundamental concepts will be developed and explored in detail (without mathematics), since they have a strong bearing on practical applications. The second purpose is to present new information and pulse measurements which will be useful in the design and applications of such devices, showing their capabilities and hitherto unexplored limitations, as derived from the fundamental concepts. Thus, this paper is partly supplementary to other published work and partly new work with the goal of providing a convenient fundamental understanding of these devices and their inherent potential and shortcomings. Although the intention is not to give a detailed design procedure, some approximate calculations and discussion of significant design criteria are included.     

A 2.4-GHz distributed antenna switch for Bluetooth transceivers

This letter describes a distributed antenna switch suitable for short-range wireless transceiver integrated circuits with a better performance in terms of insertion loss and linearity than conventional single-pole double-throw switches. The principle has been verified on a Bluetooth front-end implemented in a 0.18/spl mu/im bulk complementary metal-oxide-semiconductor technology with a supply voltage of 1.8 V.     

A lateral metal—insulator—p-Si tunnel transistor

We report the fabrication of a lateral MIS tunnel transistor whose emitter and collector are Al/SiO2/p-Si tunnel junctions. All processing is carried out at room temperature except for the growth of the passivating field oxide. The small signal common emitter current gain is 20. Two coupled gain mechanisms exist for such a lateral MIS tunnel transistor. The first mechanism relies on a high minority-carrier injection ratio of the emitter junction. Second, the minority carriers injected into the reverse-biased collector junction may produce additional gain through multiplication of majority-carrier current. Lateral MIS tunnel transistors on n-Si make use of the second mechanism. Our device takes advantage of the high minority-carrier injection ratio achievable with Al/SiO2/p-Si tunnel junctions.