Testing of hydrogen sensor based on organic materials

Práce je zaměřena na problematiku bezpečnostních vodíkových senzorů. Základní principy a teorie vodíkových senzorů je rozebrána v první části práce. Je navržena metodologie testování organických vodíkových senzorů vyvinutých a vyrobených na Fakultě Chemické Vysokého Učení Technického v Brně. Nejslibnější organický material byl testován. V závěrečné části byl navržen teplotní regulátor pro použití s keramickou senzorovou platformou.This thesis is focused on topic of safety hydrogen sensors. Theory of hydrogen sensors and main sensor principles are discussed. Methodology for testing of organic hydrogen sensors developed and fabricated at the Faculty of Chemistry of Brno University of Technology is outlined. A set of tests is done for the most promising organic material. Also, temperature regulator for ceramic sensor platform is designed.

Near-Field Microwave Microscopy of Materials Properties

Near-field microwave microscopy has created the opportunity for a new class of electrodynamics experiments of materials. Freed from the constraints of traditional microwave optics, experiments can be carried out at high spatial resolution over a broad frequency range. In addition, the measurements can be done quantitatively so that images of microwave materials properties can be created. We review the five major types of near-field microwave microscopes and discuss our own form of microscopy in detail. Quantitative images of microwave sheet resistance, dielectric constant, and dielectric tunability are presented and discussed. Future prospects for near-field measurements of microwave electrodynamic properties are also presented.Comment: 31 pages, 9 figures, lecture given at the 1999 NATO ASI on Microwave Superconductivity Changes suggested by editor, including full reference

NASA Tech Briefs, February 1989

This issue contains a special feature on shaping the future with Ceramics. Other topics include: Electronic Components & and Circuits. Electronic Systems, Physical Sciences, Materials, Computer Programs, Mechanics, Machinery, Fabrication Technology, Mathematics and Information Sciences, and Life Sciences

Single event upset testing of flash based field programmable gate arrays

In the last 50 years microelectronics have advanced at an exponential rate, causing microelectronic devices to shrink, have very low operating voltages and increased complexities; all this has made circuits more sensitive to various kinds of failures. These trends allowed soft errors, which up until recently was just a concern for space application, to become a major source of system failures of electronic products. The aim of this research paper was to investigate different mitigation techniques that prevent these soft errors in a Video Graphics Array (VGA) controller which is commonly used in projecting images captured by cameras. This controller was implemented on a Flash Based Field Programmable Gate array (FPGA). A test set-up was designed and implemented at NRF iThemba LABS, which was used to conduct the experiments necessary to evaluate the effectiveness of different mitigation techniques. The set-up was capable of handling multiple Device Under Tests (DUT) and had the ability to change the angle of incidence of each DUT. The DUTs were radiated with a 66MeV proton beam while the monitoring equipment observed any errors that had occurred. The results obtained indicated that all the implemented mitigation techniques tested on the VGA system improved the system’s capability of mitigating Single Event Upsets (SEU). The most effective mitigation technique was the OR-AND Multiplexer Single Event Transient (SET) filter technique. It was thus shown that mitigation techniques are viable options to prevent SEU in a VGA controller. The permanent SEU testing set-up which was designed and manufactured and was used to conduct the experiments, proved to be a practical option for further microelectronics testing at iThemba LABS

Electrical Characterization and Testing of Microelectronic Materials, Devices, and Circuits

This project, strengthening the microelectronics program in the Electrical and Computer Engineering Department (ECE), proposes to establish an electrical characterization and test laboratory which will provide the capability for measuring electrical properties of materials, devices, and circuits. Electrical test equipment for the measurement and characterization of dielectric materials, devices, and circuit components, will be acquired in order to provide students with hands-on experience in electrical measurements complementing the other labs in the ECE Department. In addition to providing training in microelectronics testing, the facility will allow for expanded research in the area of solid-state electronics. Focusing on material characterization, including thin films and novel gas-sensor, the project pursues the following objectives for the proposed lab: Characterizing electronic thins films, Enabling systematic characterization of novel devices including gas-sensors, and Providing a state-of-the-art capability for testing custom-designed integrated circuits. The amount of time needed to adequately test integrated circuits has been increasing with the greater level of integration in modern microelectronics. Continued increases in the density of the microelectronic circuits push against fundamental limits of device operation, driving the need for novel devices and new electronic materials. Hence, the microelectronic community should exhibit interest in a systematic approach to testing and characterization of new materials, devices, and circuits. Synergistic with existing programs at the University of Maine (e.g., sensor development, new materials development, and materials and device modeling), the project will contribute to strengthen the relationship between the ECE Department and the semiconductor industry in Maine, provide students with skills needed by these companies, and help forge relationships with research groups involved in electronic materials development

Demonstration and Validation Assets: User Manual Development

This report documents the development of a database-supported user manual for DEMVAL assets in the NSTI area of operations and focuses on providing comprehensive user information on DEMVAL assets serving businesses with national security technology applications in southern New Mexico. The DEMVAL asset program is being developed as part of the NSPP, funded by both Department of Energy (DOE) and NNSA. This report describes the development of a comprehensive user manual system for delivering indexed DEMVAL asset information to be used in marketing and visibility materials and to NSTI clients, prospective clients, stakeholders, and any person or organization seeking it. The data about area DEMVAL asset providers are organized in an SQL database with updateable application structure that optimizes ease of access and customizes search ability for the user

Marketing Plan for Demonstration and Validation Assets

The National Security Preparedness Project (NSPP), is to be sustained by various programs, including technology demonstration and evaluation (DEMVAL). This project assists companies in developing technologies under the National Security Technology Incubator program (NSTI) through demonstration and validation of technologies applicable to national security created by incubators and other sources. The NSPP also will support the creation of an integrated demonstration and validation environment. This report documents the DEMVAL marketing and visibility plan, which will focus on collecting information about, and expanding the visibility of, DEMVAL assets serving businesses with national security technology applications in southern New Mexico

Fundamental Studies of Tin Whiskering in Microelectronics Finishes

Fundamental Studies of Tin Whiskering in Microelectronics Finishes Abstract Common electronics materials, such as tin, copper, steel, and brass, are ambient reactive under common use conditions, and as such are prone to corrosion. During the early 1940s, reports of failures due to electrical shorting of components caused by `whisker' (i.e., filamentary surface protrusion) growth on many surface types - including the aforementioned metals - began to emerge. Lead alloying of tin (3-10% by weight, typically in the eutectic proportion) eliminated whiskering risk for decades, until the July 2006 adoption of the Restriction of Hazardous Substances (RoHS) directive was issued by the European Union. This directive, which has since been adopted by California and parts of China, severely restricted the use of lead (<1000 ppm) in all electrical and electronics equipment being placed on the EU market, imposing the need for developing reliable new "lead-free" alternatives to SnPb. In spite of the abundance of modern-day anecdotes chronicling whisker-related failures in satellites, nuclear power stations, missiles, pacemakers, and spacecraft navigation equipment, pure tin finishes are still increasingly being employed today, and the root cause(s) of tin whiskering remains elusive. This work describes a series of structured experiments exploring the fundamental relationships between the incidence of tin whiskering (as dependent variable) and numerous independent variables. These variables included deposition method (electroplating, electroless plating, template-based electrochemical synthesis, and various physical vapor deposition techniques, including resistive evaporation, electron beam evaporation, and sputtering), the inclusion of microparticles and organic contamination, the effects of sample geometry, and nanostructuring. Key findings pertain to correlations between sample geometry and whisker propensity, and also to the stress evolution across a series of 4"-diameter silicon wafers of varying thicknesses with respect to the degree of post-metallization whiskering. Regarding sample geometry, it was found that smaller, thinner substrates displayed a more rapid onset of whiskering immediately following metallization. Changes in wafer-level stress were not found to correlate with whiskering morphology (number, density, length) after 6 weeks of aging. This result points either to the irrelevance of macrostress in the substrate/film composite, or to a difference in whiskering mechanism for rigid substrates (whose stress gradient over time is significant) when compared with thinner, flexible susbtrates (whose stress is less variable with time). Organic contamination was found to have no appreciable effect when explicitly introduced. Furthermore, electron-beam evaporated films whiskered more readily than films deposited via electroplating from baths containing organic "brighteners." Beyond such findings, novel in themselves, our work is also unique in that we emphasize the "clean" deposition of tin (with chromium adhesion layers and copper underlayers) by vacuum-based physical vapor deposition, to circumvent the question of contamination entirely. By employing silicon substrates exclusively, we have distinguished ourselves from other works (which, for example, use copper coupons fabricated from rolled shim stock) because we have better sample-to-sample consistency in terms of material properties, machinability, and orientation