8,765 research outputs found
Design, processing and testing of LSI arrays hybrid microelectronics task
Those factors affecting the cost of electronic subsystems utilizing LSI microcircuits were determined and the most efficient methods for low cost packaging of LSI devices as a function of density and reliability were developed
Chalcogenide Glass-on-Graphene Photonics
Two-dimensional (2-D) materials are of tremendous interest to integrated
photonics given their singular optical characteristics spanning light emission,
modulation, saturable absorption, and nonlinear optics. To harness their
optical properties, these atomically thin materials are usually attached onto
prefabricated devices via a transfer process. In this paper, we present a new
route for 2-D material integration with planar photonics. Central to this
approach is the use of chalcogenide glass, a multifunctional material which can
be directly deposited and patterned on a wide variety of 2-D materials and can
simultaneously function as the light guiding medium, a gate dielectric, and a
passivation layer for 2-D materials. Besides claiming improved fabrication
yield and throughput compared to the traditional transfer process, our
technique also enables unconventional multilayer device geometries optimally
designed for enhancing light-matter interactions in the 2-D layers.
Capitalizing on this facile integration method, we demonstrate a series of
high-performance glass-on-graphene devices including ultra-broadband on-chip
polarizers, energy-efficient thermo-optic switches, as well as graphene-based
mid-infrared (mid-IR) waveguide-integrated photodetectors and modulators
Realization of fully distributed RC networks using thick film technology
The problems associated with the fabrication of Fully
Distributed RC (FDRC) networks using thick film techniques have been discussed. Also, a comprehensive investigation into the fabrication of fully distributed RC networks has been carried out in which a series of resistor-dielectric ink combinations were examined for compatibility. The investigations resulted in the successful fabrication of thick film FDRC devices.
It must be mentioned, however, that the conventional methods
of trimming could not be used in view of the fact that the first
resistor layer of the FDRC network is completely covered with a layer of dielectric and that the physical shape and size of the distributed network should not be changed by trimming. The high voltage pulse trimming technique was therefore examined in detail since it neither required accessibility to the surface of the resistor nor did it change the physical shape of the resistors. A suitable electronic circuit was designed for this purpose and was used to adjust the values of several fully distributed RC components.
The manufactured thick film FDRC devices was examined in
various electronic networks such as multivibrators, phase shift
oscillators and active filters with successful results
Design, processing and testing of LSI arrays, hybrid microelectronics task
Mathematical cost models previously developed for hybrid microelectronic subsystems were refined and expanded. Rework terms related to substrate fabrication, nonrecurring developmental and manufacturing operations, and prototype production are included. Sample computer programs were written to demonstrate hybrid microelectric applications of these cost models. Computer programs were generated to calculate and analyze values for the total microelectronics costs. Large scale integrated (LST) chips utilizing tape chip carrier technology were studied. The feasibility of interconnecting arrays of LSU chips utilizing tape chip carrier and semiautomatic wire bonding technology was demonstrated
Thermoelectric Outer Planets Spacecraft (TOPS) electronic packaging and cabling development summary report
Electronic packaging and cabling activities performed in support of the Thermoelectric Outer Planets Spacecraft (TOPS) Advanced Systems Technology (AST) project are detailed. It describes new electronic compartment, electronic assembly, and module concepts, and a new high-density, planar interconnection technique called discrete multilayer (DML). Development and qualification of high density cabling techniques, using small gage wire and microminiature connectors, are also reported
Multilayer microwave structures using thick-film technology.
Multilayer techniques, in conjunction with thick-film technology have been applied to the design and fabrication of several multilayer microwave structures to achieve the low cost and high performance goals set by modern microwave circuits and systems.
To provide accurate material parameters for the design of multilayer thick-film components, a novel slit cavity resonator method has been developed that enables the relative permittivity and loss tangent of dielectric samples to be measured easily, and with high accuracy. A particular feature of this method is that it can be used to measure thick-film samples that are normally only available in relatively thin layers in a two-layer format. Rigorous electromagnetic analysis on a slit cavity has been performed that accounts for the effect of the fringing fields and the radiation from the slits. The method has been verified through measurement on several thick-film materials over X-band. Both the analytical methods and the fabrication techniques for multilayer microwave microstrip structures are presented. Several multilayer thick-film microstrip line test
structures have been designed and characterised, and these provide a basic database for the design of multilayer microstrip components.
A new design procedure for the multilayer end-coupled filter has been developed that enables the designer to arrive at the physical dimensions of the multilayer structure based on the filter specification. This design technique is effective as it combines the accuracy of electromagnetic (EM) analysis and the efficiency of circuit simulation.
The multilayer gap, which is the most critical element of multilayer end-coupled filters, has been characterised using EM analysis and the data is incorporated into a circuit simulator. Measured and simulated results are presented that verify the new design technique. A 40% bandwidth has been achieved experimentally, which shows a very significant improvement over conventional single layer structures, where the bandwidth achievable is normally less than 5%. Novel, octave band DC blocks have been designed, fabricated and tested using a new multilayer format. The tight coupling required between the coupled lines in this component was realized by overlapping these lines in a multilayer structure. Very good agreement was obtained between measured and simulated data. The multilayer approach was also applied to the design of coupled line bandpass filters where a measured 80% bandwidth was achieved. For the first time, the properties of multilayer coupled lines using a range of different thick-film dielectrics are examined using their coupled-mode parameters. Design curves for multilayer coupled lines are obtained, that provide important information on the design of multilayer directional couplers.
A practical design strategy for multilayer directional couplers is developed, which overcomes the problem of excessive computation that is normally associated with the electromagnetic optimization of multilayer circuit designs. The methodology has been verified through the design and measurement of wide bandwidth 2dB and 3dB directional couplers that were fabricated using multilayer, thick-film technology. New techniques for the design and fabrication of multilayer microwave thick-film components have thus been established, both theoretically and through practical circuit fabrication and measurement
Thick film resistors on dielectrics
This thesis investigates the viability of using thick film materials on a range of thick film dielectrics. They are usually
formulated so as to be compatible with 96% alumina substrates. It is sometimes desirable, however, to deposit them on thick film dielectrics. This may produce both technical and commercial advantages. The electrical changes produced and the chemical interactions observed are discussed. It is concluded that viable systems are possible provided the materials are carefully selected. In particular, there is evidence that the presence of barium in a resistor material affects the conduction mechanisms. This means that, in cases where the dielectric contains barium, the effects on the properties of the resistors may be very marked.
It is observed, however, that ceramic filled dielectrics with a high content of glasses should form a satisfactory class of
dielectric for use as an underlayer for thick film resistors. This conclusion appears to be in agreement with recently published commercial developments.
The thesis also discusses materials selection and the preparation of samples and gives detailed results of electrical tests. The figures includes plots of the results of SEM/EDX analyses made on polished cross-sections of samples
- …