P-I-N isolation for monolithic integrated circuits

A new isolation scheme is described in which the device is fabricated in an intrinsic region isolated from other regions and from theP^{+}substrate by aP-I-Nstructure. Thus the component-to-substrate capacitance and the substrate resistance are reduced by one order of magnitude or more, and the coupling or crosstalk is consequently reduced by several orders of magnitude. The fabrication process involves only conventional epitaxy and diffusion techniques. The intrinsic regions are obtained through gold compensation. Compared toP-N-junction-isolated gold-doped integrated devices, theP-I-N-isolated circuits require only one additional step-a second epitaxial deposition. Preliminary experimental data giveP-I-Ncapacitance of about 0.013 pF/mil²and breakdown voltage of 200 volts.     

Proton isolation for GaAs integrated circuits

Significant improvement in the electrical isolation of closely spaced GaAs integrated circuit (IC) devices has been achieved with proton implantation. Isolation voltages have been increased by a factor of four in comparison to a selective implant process. In addition, the tendency of negatively biased ohmic contacts to reduce the current flow in neighboring MESFET's (backgating) has been reduced by at least a factor of three. The GaAs IC compatible process includes implantation of protons through the SiO2field oxide and a three-layered dielectric-Au mask which is definable to 3-µm linewidths and is easily removed. High temperature storage tests have demonstrated that proton isolation, with lifetimes on the order of 10⁶h at 290°C, is not a lifetime limiting component in a GaAs IC process.     

Measurement techniques for monolithic microwave integrated circuits

Introduces the basic technologies that are associated with measurements of monolithic microwave integrated circuits. The use of test fixtures and wafer probe stations at ambient room temperature is reviewed and their role at thermal and cryogenic temperatures is discussed. With the increasing need for performing non-invasive measurements, advances in experimental field probing techniques are explored     

Uniplanar techniques for monolithic microwave integrated circuits

`Uniplanar' techniques have recently been introduced for the design of monolithic microwave integrated circuits (MMICs). The aim of these techniques is to achieve a higher level of integration of circuitry and to overcome the need for through-substrate via holes and the related back-face processing steps. This is achieved by using coplanar waveguide (CPW), slotline, and miniature `thin-film microstrip' transmission-line media as opposed to conventional microstrip. The design and performance of a number of uniplanar MMIC couplers, amplifiers, and other test circuits fabricated using the GEC-Marconi (Caswell) foundry are described     

High-purity semi-insulating GaAs material for monolithic microwave integrated circuits

Liquid-Encapsulated Czochralski (LEC) growth of large-diameter bulk GaAs crystals from pyrolytic boron nitride (PBN) crucibles has been shown to yield high crystal purity, stable high resistivities, and predictable direct ion-implantation characteristics. Undoped (≲low 10¹⁴cm^-3chromium) and lightly Cr-doped (low 10¹⁵cm^-3range) -GaAs crystals, synthesized and pulled from PBN crucibles contain residual shallow donor impurities typically in the mid 10¹⁴cm^-3, exhibit bulk resistivities above 10⁷Ω . cm, and maintain the high sheet resistances required for IC fabrication (>10⁶Ω/□) after implantation anneal. Direct²⁹Si channel implants exhibit uniform (± 5 percent) and predictable LSS profiles, high donor activation (75 percent), and 4800- to 5000-cm²/V . s mobility at the (1 to 1.5) × 10¹⁷cm^-3peak doping utilized for power FET's. It has also been established that LEC crystals can provide the large-area, round     

The evolution of packages for monolithic microwave andmillimeter-wave circuits

The maturing of monolithic microwave integrated circuit (MMIC) technology has spawned a variety of new military and commercial applications. As-a result, there is an increased emphasis on the packaging of MMIC chips and MMIC-based components. Currently, the industry is applying a number of new assembly and packaging technologies to RF components and subsystems driven by the forces of performance, size and weight, and cost. This paper outlines the current evolution in microwave and millimeter-wave packaging using examples drawn from the area of active array antennas     

Approach for heat sinks in monolithic microwave integrated circuits

A planar electrode, placed at the symmetry plane of the odd mode of coupled microstrip, is proposed as a means for heat-sinking active devices in monolithic microwave integrated circuits.     

Optimization of diode structures for monolithic integrated microwave circuits

Device requirements of a medium power Ku-band reflective phase shifter are reviewed indicating a requirement for a diode with a 4-Terrahertz cut-off frequency. Various structures are examined to test their suitability for integration and feasibility for meeting specifications. A "pocket version" of a surface oriented device design is chosen and described. It is shown to meet or exceed all electrical requirements while providing for compatibility with final integration into the circuit.     

Low-noise high electron mobility transistors for monolithic microwave integrated circuits

High electron mobility transistors (HEMT's) for monolithic microwave integrated circuits have been fabricated that have demonstrated excellent performance. External transconductance of 300 mS/mm is observed and noise figures of 1 and 1.8 dB with associated gains of 16.1 and 11.3 dB at 8 and 18 GHz, respectively, have been measured. These are comparable to the best reported noise figures for either HEMT's or MESFET's and are the highest associated gains reported for such low-noise figures. Analysis of these devices indicates that further improvements in these results is possible through optimization of HEMT layers and fabrication technology to reduce gate-source parasitic resistance.     

Periodic slow-wave low-loss structures for monolithic GaAs microwave integrated circuits

Slow-wave structures on GaAs semi-insulating substrate, obtained by periodically loading a coplanar line with high-Q overlap capacitors, are described. They operate up to X-band, reducing significantly the signal phase velocity by a factor nearly independent of the frequency. Owing to their low transmission losses, they are particularly suitable for monolithic GaAs f.e.t. circuits.     

Shielded passive devices for silicon-based monolithic microwave and millimeter-wave integrated circuits

This paper introduces floating shields for on-chip transmission lines, inductors, and transformers implemented in production silicon CMOS or BiCMOS technologies. The shield minimizes losses without requiring an explicit on-chip ground connection. Experimental measurements demonstrate Q-factor ranging from 25 to 35 between 15 and 40 GHz for shielded coplanar waveguide fabricated on 10 /spl Omega//spl middot/cm silicon. This is more than a factor of 2 improvement over conventional on-chip transmission lines (e.g., microstrip, CPW). A floating-shielded, differentially driven 7.4-nH inductor demonstrates a peak Q of 32, which is 35% higher than an unshielded example. Similar results are realizable for on-chip transformers. Floating-shielded bond-pads with 15% less parasitic capacitance and over 60% higher shunt equivalent resistance compared to conventional shielded bondpads are also described. Implementation of floating shields is compatible with current and projected design constraints for production deep-submicron silicon technologies without process modifications. Application examples of floating-shielded passives implemented in a 0.18-/spl mu/m SiGe-BiCMOS are presented, including a 21-26-GHz power amplifier with 23-dBm output at 20% PAE (at 22 GHz), and a 17-GHz WLAN image-reject receiver MMIC which dissipates less than 65 mW from a 2-V supply.     

Technology for monolithic high-power integrated circuits using polycrystalline Si for collector and isolation walls

The fabrication technology for a high-power monolithic IC improved the breakdown characteristics and the output current capability. The maximum output power increased to 50 W and the supplied voltage of 110 V was realized. Highly doped polycrystalline Si was used as the collector walls and the isolation walls of transistors. Electrical and physical properties of the polycrystalline structure used in the power IC and the fabrication technology are also described.     

Pseudomorphic high electron mobility transistor monolithic microwave integrated circuits reliability study

Accelerated high temperature RF life testing was used to investigate the reliability of two-stage GaAs monolithic microwave integrated circuit (MMIC) power amplifiers based on 0.25 μm pseudomorphic high electron mobility transistor technology. Life testing was performed at elevated baseplate temperatures with MMICs operating at typical d.c. bias conditions and large signal RF drive levels of two dB compression. The resulting failure distribution was log normal and the estimated median life time extrapolated to a channel temperature of 140°C was 2.3×10⁶ h with an activation energy of 1.1 eV.     

Large-value monolithic resistors for micropower integrated circuits

The minimum power dissipation of micropower integrated circuits is often limited by the availability of large-value monolithic resistors. Two major types of field-effect resistor structures are examined and an analysis of the primary factors that determine sheet resistance and parasitic capacitance is presented. Resistor tolerance, linearity, and temperature coefficient are briefly discussed. It is shown that resistors with sheet resistances greater than 50 k/spl Omega///spl square/ and parasitic capacitances less than 0.002 pF/k/spl Omega/ can be readily fabricated in a monolithic structure.     

MICROX-an all-silicon technology for monolithic microwaveintegrated circuits

An improved silicon-on-insulator (SOI) approach offers devices and circuits operating to 10 GHz by providing formerly unattainable capabilities in bulk silicon: reduced junction-to-substrate capacitances in FETs and bipolar transistors, inherent electrical isolation between devices, and low-loss microstrip lines. The concept, called MICROX (patent pending), is based on the SIMOX process, but uses very-high-resistivity (typically>10000 Ω-cm) silicon substrates, MICROX NMOS transistors of effective gate length 0.25 μm give a maximum frequency of operation, f_max, of 32 GHz and f_T of 23.6 GHz in large-periphery (4 μm×50 μm) devices with no correction for the parasitic effects of the pads. The measured minimum noise figure is 1.5 dB at 2 GHz with associated gain of 17.5 dB, an improvement over previously reported values for silicon FETs     

Quantitative high frequency-electric force microscope testing of monolithic microwave integrated circuits at 20 GHz

Recently, a High Frequency-Electric Force Microscope (HF-EFM) test system has been successfully used for contactless testing of internal electric signals in Monolithic Microwave Integrated Circuits (MMIC). Measurements up to operating frequencies of 110 GHz have been demonstrated. The underlying measurement principle is the heterodyne mixing technique which transforms HF-signals in a lower frequency range, where the detected signal can be easily processed further on. Different ways exist to realize the heterodyne mixing technique in an EFM. The normally used way, the so-called conventional mixing technique (CMT), generates the low frequency signal by mixing the to be measured MMIC internal test point signal with a second HF-signal of a slightly different frequency which is applied to the probe. However, this way of generating the low frequency signal excludes up to now a quantitative measurement of a high frequency test point signal. In this paper an alternative mixing technique, the so-called amplitude modulation technique (AMT), is introduced in order to overcome the disadvantages of the CMT and, additionally, simplify the experimental set up. Quantitative high frequency measurements at 20 GHz demonstrate the efficiency of this new technique.     

CAD techniques for microwave circuits

In little more than 10 years computer-aided design (CAD) of microwave circuits has moved from dumb terminals on mainframe computers to PCs, and now to powerful RISC workstations. Commercial CAD software now integrates the various stages of microwave circuit design: schematic capture, simulation and layout. This paper reviews the different CAD packages that are available for microwave circuit design. The basic principles employed in the modelling of microstrip circuits are introduced and the reasons for the extensive use of frequency-domain simulations are explored. The developments in nonlinear, electromagnetic and system-level simulation methods are described     

Tantalum oxide capacitors for GaAs monolithic integrated circuits

The performance of a high-yield tantalum oxide capacitor for use in GaAs monolithic microwave integrated circuits is described. The integral metal-insulator-metal sandwich structure is reactively sputter-deposited at low temperatures, compatible with a photoresist lift-off process, on semi-insulating GaAs substrate. Dielectric constants of 20-25 were achieved in the capacitors fabricated. An initial application of this process as an interstage coupling capacitor for a two-stage preamplifier is given.     

A new air-isolation process for monolithic integrated circuits

A new air-isolation process is described which overcomes many of the problems of existing isolation technologies. The process consists of standard integrated circuit processing except for the p-n junction isolation process which is omitted. After metal mask, the device wafer is glass bonded face down to a supporting silicon wafer. Subsequent backlapping, masking, and mesa etching steps yield an air-isolated integrated circuit. As one application of this technology, the fabrication of a radiation-hardened operational amplifier is described.