Development of a high capacity bubble domain memory element and related epitaxial garnet materials for application in spacecraft data recorders. Item 1: Development of a high capacity memory element

Several versions of the 100K bit chip, which is configured as a single serial loop, were designed, fabricated and evaluated. Design and process modifications were introduced into each succeeding version to increase device performance and yield. At an intrinsic field rate of 150 KHz the final design operates from -10 C to +60 C with typical bias margins of 12 and 8 percent, respectively, for continuous operation. Asynchronous operation with first bit detection on start-up produces essentially the same margins over the temperature range. Cost projections made from fabrication yield runs on the 100K bit devices indicate that the memory element cost will be less than 10 millicents/bit in volume production

Procedures for precap visual inspection

Screening procedures for the final precap visual inspection of microcircuits used in electronic system components are described as an aid in training personnel unfamiliar with microcircuits. Processing techniques used in industry for the manufacture of monolithic and hybrid components are presented and imperfections that may be encountered during this inspection are discussed. Problem areas such as scratches, voids, adhesions, and wire bonding are illustrated by photomicrographs. This guide can serve as an effective tool in training personnel to perform precap visual inspections efficiently and reliably

Linear laser diode arrays for improvement in optical disk recording for space stations

The design and fabrication of individually addressable laser diode arrays for high performance magneto-optic recording systems are presented. Ten diode arrays with 30 mW cW light output, linear light vs. current characteristics and single longitudinal mode spectrum were fabricated using channel substrate planar (CSP) structures. Preliminary results on the inverse CSP structure, whose fabrication is less critically dependent on device parameters than the CSP, are also presented. The impact of systems parameters and requirements, in particular, the effect of feedback on laser design is assessed, and techniques to reduce feedback or minimize its effect on systems performance, including mode-stabilized structures, are evaluated

Retention and application of Skylab experiences to future programs

The problems encountered and special techniques and procedures developed on the Skylab program are described along with the experiences and practical benefits obtained for dissemination and use on future programs. Three major topics are discussed: electrical problems, mechanical problems, and special techniques. Special techniques and procedures are identified that were either developed or refined during the Skylab program. These techniques and procedures came from all manufacturing and test phases of the Skylab program and include both flight and GSE items from component level to sophisticated spaceflight systems

Parts, materials, and processes experience summary, volume 2

This summary provides the general engineering community with the accumulated experience from ALERT reports issued by NASA and the Government-Industry. Data Exchange Program, and related experience gained by Government and industry. It provides expanded information on selected topics by relating the problem area (failure) to the cause, the investigation and findings, the suggestions for avoidance (inspections, screening tests, proper part applications, requirements for manufacturer's plant facilities, etc.), and failure analysis procedures. Diodes, integrated circuits, and transistors are covered in this volume

Radiation Effects on the Electrical Properties of Hafnium Oxide Based MOS Capacitors

Hafnium oxide-based MOS capacitors were investigated to determine electrical property response to radiation environments. In situ capacitance versus voltage measurements were analyzed to identify voltage shifting as a result of changes to trapped charge with increasing dose of gamma, neutron, and ion radiation. In situ measurements required investigation and optimization of capacitor fabrication to include dicing, cleaning, metalization, packaging, and wire bonding. A top metal contact of 200 angstroms of titanium followed by 2800 angstroms of gold allowed for repeatable wire bonding and proper electrical response. Gamma and ion irradiations of atomic layer deposited hafnium oxide on silicon devices both resulted in a midgap voltage shift of no more than 0.2 V toward less positive voltages. This shift indicates recombination of radiation induced positive charge with negative trapped charge in the bulk oxide. Silicon ion irradiation caused interface effects in addition to oxide trap effects that resulted in a flatband voltage shift of approximately 0.6 V also toward less positive voltages. Additionally, no bias dependent voltage shifts with gamma irradiation and strong oxide capacitance room temperature annealing after ion irradiation was observed. These characteristics, in addition to the small voltage shifts observed, demonstrate the radiation hardness of hafnium oxide and its applicability for use in space systems

Index to 1984 NASA Tech Briefs, volume 9, numbers 1-4

Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1984 Tech B Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

Microtechnologies for Discharge-based Sensors.

Microdischarge-based sensors are known to offer advantages such as the ability to operate at temperature extremes and to provide large output signals that do not require local amplification. This work is primarily directed at the design and microfabrication of pressure sensors that use differential microdischarge currents. Two approaches are evaluated. The first uses a common anode and reference cathode located on a glass substrate, whereas a sensing cathode is located on an opposing silicon diaphragm that is deflected by applied pressure. Leads are transferred by electroplated through-glass vias. The second uses a common cathode and reference anode located on a silicon substrate, whereas a sensing anode is located on a thin film diaphragm that deflects under applied pressure. Leads are transferred by through-wafer isolated bulk-silicon lead transfer (TWIST). Fabricated sensors with 200-µm diameter have footprints as small as 300×300 µm2, and volume of ≈0.01 mm3, which is 150× smaller than prior work. The fractional differential current (I1-I2)/(I1+I2) increases monotonically from -0.7 to 0.2 as external pressure increases from 1 atm to 8 atm. The TWIST process can also be used to fabricate ultra-miniature capacitive pressure sensors with backside contacts that minimize the form factor and allow stacking of the sensor on interface electronics. A sensor with a 100-µm diameter diaphragm measures 150×150 µm2 in size. Fabricated sensors with thicknesses of 3 µm (C100t3) and 5 µm (C100t5) have dynamic ranges of 20 MPa and 50 MPa, respectively. Pressure responses in the non-contact mode and the contact mode are 3.1 fF/MPa, 5.3 fF/MPa for C100t3, and 1.6 fF/MPa, 1.6 fF/Ma for C100t5, respectively. This thesis also describes a preliminary exploration of options to initiate microdischarges using scavenged energy – in this case from mechanical impact. A miniature high voltage generator is formed by connecting multiple electrode pairs in series on a single PZT element. This strategy amplifies voltage roughly in proportion to the electrode pair count; a three electrode-pair device is used to successfully initiate microdischarges with peak voltages exceeding 1.35 kV.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111467/1/xinluo_1.pd

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