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Device with step function variation of the capacitance is useful for voltage-controlled oscillator circuits and as a voltage-sensitive switch. Simplicity of construction makes the device suitable for large-scale integration, microelectronic circuits.
Large scale integration and metal oxide semiconductor microelectronic testing techniques including combinatorial, sequential, functional, and parametric methods
Large scale integration microelectronic wafer and package testing including parametric and functional tests of combinatorial and sequential logic circuits
Microelectronics program was initiated to evaluate circuitry, packaging methods, and fabrication approaches necessary to produce completely procured logic system. Two autowire programs were developed for CDC-3200 and IBM-360 computers for use in designing logic systems.
Strain sensors that can be switched on and off were fabricated from p-channel IGFET on thin filament n-type silicon crystals with silicon dioxide layer sputtered over transistor for passivation. Applications include integration with microelectronic circuits for multiplexing.
The Weld Quality Monitor has provided online control through the application of linear transducers. The electronic systems must be upgraded to increase confidence level required in production. The Weld Quality Monitor has been used with a recent model solid state power supply to evaluate ability to differentiate between sound and defective weld joints. The Weld Quality Monitor has been evaluated on Dumet and Kovar to interconnect materials Nickel and Alloy 180 in weld joints used on microelectronic module fabrication. Distinct separation was achieved between low strength welds and sound welds by the Quality Monitor. Evaluation performed indicates a drift level at less than 2 percent on a series of 50 consecutive welds. Operation under shop conditions identified need for controlled electrode impact. This was achieved with pneumatic actuation.
The design and fabrication of telemetry ground data processing equipment using commercial logic cards or modules are discussed. A microelectronics program was initiated to evaluate circuitry, packaging methods, and fabrication approaches necessary to produce a competitively procured logic system. The NAS-PAK logic system covering all phases of implementation is considered.
Circuitry has been developed for digital control of the Canopus tracker. A feasibility and demonstration breadboard has been constructed using microelectronic integrated circuits. The breadboard contains the digital circuits necessary for closed-digital logic necessary for star acquisition, particle rejection, programmable gate selection, cone angle selection, and routing of the digital roll error signal.
Two rotating data systems for engine component testing which demonstrate the techniques of on-the-shaft microelectronic signal conditioning and rotary transformer power- and data-transfer are described. (1) A digital data system provides 69 channels of 1100 C maximum thermocouple data with less than 0.5 percent error from a turbine test rig rotating at speeds up to 9000 rpm. (2) An analog data system amplifies and transfers 72 channels of dynamic strain data with less than 5 percent error from a compressor rig at speeds above 14,000 rpm.
The electrical and electrochemical properties of V-5 and V-7 vanadium oxides were investigated. The effects of pressure, temperature and moisture on the bulk resistivity of the oxides in powder, sintered, and crystalline form were determined, and the static and dynamic volt-ampere characteristics were obtained. Sintered samples tested showed better electrical stability than the compressed powder samples. Two types of commercially available vanadium pentoxide were heat-treated to obtain various crystalline oxide forms which were mounted on alumina substrates and terminated by thick-film conductors for making electrical connections. Indications are that these materials could have applications as sensors, critical-temperature resistors, high-speed switches, and temperature-compensation elements in hybrid microelectronic circuits.
Hybrid microelectronics relay has characteristics significantly superior to conventional solid state relays. Relay provides 2500 Vdc input to output isolation and operates from high threshold logic signal to switch load of 400 Vdc at 2 mA. Technology should be of interest to manufacturers of discrete components.
Although it is generally accepted that the use of adhesives in the assembly of hybrid microcircuits offers advantages over other bonding methods, there currently does not exist a set of guidelines for the selection of adhesives which will insure that hybrid microcircuits assembled with them will meet the long use-life, high-reliability requirements of electronic equipment for space applications. This study was directed to the identification of the properties of electrically insulative adhesives that potentially could cause problems in such an application, and to the development of evaluation tests to quantify these properties and thus form the basis for establishing suitable guidelines and, ultimately, specifications. Bond strength, outgassing after cure, and corrosivity were selected for detailed attention since they are considered to be especially critical. Introductory discussion includes enumeration and brief comments on the properties of adhesives considered to be important for the proposed application, a general review of polymeric types of adhesives, and identification of the major types of adhesives commercially available and specifically designed for microelectronic use. The specific tests developed to evaluate bond strength, outgassing after cure, and corrosivity are discussed in detail, and comparative results obtained for selected adhesives representative of the major types are given.
A family of computer programs facilitating the design, layout, evaluation, and testing of digital electronic circuitry is described. CADAT (computer aided design and test system) is intended for use by NASA and its contractors and is aimed predominantly at providing cost effective microelectronic subsystems based on custom designed metal oxide semiconductor (MOS) large scale integrated circuits (LSIC's). CADAT software can be easily adopted by installations with a wide variety of computer hardware configurations. Its structure permits ease of update to more powerful component programs and to newly emerging LSIC technologies. The components of the CADAT system are described stressing the interaction of programs rather than detail of coding or algorithms. The CADAT system provides computer aids to derive and document the design intent, includes powerful automatic layout software, permits detailed geometry checks and performance simulation based on mask data, and furnishes test pattern sequences for hardware testing.
Description of research and development efforts which resulted in a high-voltage cryoelectron microscope system capable of consistent operation at 1.8 to 4.2 K. Attention is given to the design and operation of superconducting objective lenses providing enhanced resolution during longer exposure times at lower beam intensities (thus reducing radiation damage of specimens). A specific system described combines a closed-cycle superfluid helium refrigerator integrated with a modified 200 kV electron microscope. Consistent resolutions of 8 to 16 A are attained with significantly reduced radiation damage, contamination, and thermal noise in prolonged vibration-free examination of specimens at temperatures from 1.8 to 4.2 K. Applications in specific disciplines are discussed, including membrane ultrastructure, cryobiology, microelectronics, and general superconductivity research.
Two rotating data systems for engine component testing, which demonstrate the techniques of on-the-shaft microelectronic signal conditioning and rotary transformer power- and data-transfer, are described. These systems are a digital data system which provides 69 channels of 1100 C maximum thermocouple data with less than 0.5% error from a turbine test rig rotating at speeds up to 9000 rpm and an analog data system which amplifies and transfers 72 channels of dynamic strain data with less than 5% error from a compressor rig at speeds above 14,000 rpm.
Present practices in lightning protection of aircraft deal primarily with the direct effects of lightning, such as structural damage and ignition of fuel vapors. There is increasing evidence of troublesome electromagnetic effects, however, in aircraft employing solid-state microelectronics in critical navigation, instrumentation and control functions. The potential impact of these indirect effects on critical systems such as digital fly-by-wire (DFBW) flight controls has been studied by several recent research programs, including an experimental study of lightning-induced voltages in the NASA F8 DFBW airplane. The results indicate a need for positive steps to be taken during the design of future fly-by-wire systems to minimize the possibility of hazardous effects from lightning.
The development of an S-band antenna phased array for spacecraft to spacecraft communication is discussed. The system requirements, antenna array subsystem design, and hardware implementation are examined. It is stated that the phased array approach offers the greatest simplicity and lowest cost. The objectives of the development contract are defined as: (1) design of a medium gain active phased array S-band communications antenna, (2) development and test of a model of a seven element planar array of radiating elements mounted in the appropriate cavity matrix, and (3) development and test of a breadboard transmit/receive microelectronics module.