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From page 41... ... pulsars and about fou r years on six newly discovered pulsars The phase measurements are available f o r analysis as geocentric and barycentnc arrival times Raw data records are available as 500- to 1500-pulse integrations fo r durations o f one to three hours This data set was collected using the NASA Deep Space Network facilities at a frequency o f 2295 M H z Other Activities in progress include staUstical studies o f the timing residuals as oudined by Cordes (1980) and an experiment to detect gravitational waves by searching Uming data f o r the effects o f wave-induced perturbations m the Earth-pulsar distance Preprints o f work recently submitted fo r publication are available upon request Reference G S Downs & P E Reichler, Ap J SuppI 53, 169(1983) Read the entire page →
From page 42... ... urement of Seebeck coefficient, electrical conducUvity, thermal diffusity, and Hall effect are available for these studies Thin-Film Deposition and Device Fabrication for Advanced Electron Devices RJ Stirn 44 40 10 02 Ongoing work at J PL includes exploring the use of chemical vapor deposition, magnetron sputtering, spray pyrolysis, and physical evaporation techniques for the growth of thin-film materials suitable for electron device application Examples of applications are solar cells of higher-conversion efficiency, lowered cost, and improved radiation resistance for space and terrestrial application, GaAs heterostructurs for high-speed low-power FET's and milhmeter-wave devices, and infrared detectors operating in the photovoltaic or photoconductive mode In the area of CVD research, the use of low-pressure and laser photolyic enhancement is of interest in low-temperature deposition and/or improved growth rates and abrupt interfaces between semiconductors Facilities exist for reactive sputter deposition of binary and ternary semiconductors using hydrogen selenide and hydrogen sulfide gases as well Characterizauon facilities available for these investigauons include (1) scanning electron and optical microscopy, x-ray diffraction, EDAX, lon-microprobe, photoluminescence, reflection and transmission spectrophomometry, laser scanning for annealing and/or recrystallization, and (2) Read the entire page →
From page 43... ... dielectrics with capacitor processing and performance is of particular importance The work involves use of a wide range of quanutauve analytical techniques to assess the thermal, chemical, and structural characteristics of dielectric fluids and polymeric films Wave-Front Propagation N.I Marzwell 44 40 10 05 The physics of high-energy laser systems wave front is analyzed in terms of its diagnosucs, controls, and correction for signal and power transmission through the atmosphere or sea waters Atmospheric transmission and propagation problems attenuate and reduce the quality of the laser energy and limit its applications. To overcome this limitauon, research has been iniuated to understand how laser beams are being impacted with humidity, crosswind, turbulence, slew rate, aperture, and range Methods to optimize the beam quality and to control its poinung accuracy as it propagates through the atmosphere or sea water are being investigated Emphasis is being placed on methods of acuve controls of the optical systems, from controlling a mirror in six degrees of freedom up to systems employing segmented or deformable mirrors that may possess more than 100 degrees of freedom Diagnostic techniques that are being studied include wavefront conjugation and four-wave mixing The purpose of this research is (1) Read the entire page →
From page 44... ... an autoregressive model to fit the input-output data from the manipulator to achieve higher manipulator-motion accuracies Adaptive Self-Tuning Control of Manipulators in Task-Coordinated System N I Marzwell 44 40 10 07 The dynamic motion of a manipulator is strongly influenced by the mechanical and material properties associated with the manipulator design and environment in which the manipulator is expected to perform Link masses, inertial loadings, joint friction, sensor compliance, link flexibility, and actuator dynamics all couple with load impedance and gravity effects to provide a highly interactive, crosscoupled, nonlinear dynamic system Research is being pursued to address the contro-system design strategies and requirements of dynamic mouon in terms of the changing dynamic configurations, as well as load variability factors Macromolecular Melts and Glasses J Moacanin 44 40 10 08 The equation-of-state (PVT) description of macromolecules in both the melt and glassy states is developed rather well The theory is applicable to single-phase as well as multiphase systems. Read the entire page →
From page 45... ... Superconductor-Insulator-Superconductor (SIS) Mixer for Submillimeter-Wave Heterodyne Receiver S K Khanna 44 40 10 10 Superconductor-Insulator-Superconductor (SIS) Read the entire page →
From page 46... ... GaAs and Silicon Transistor-Device Models for Highly Reliable Integrated Circuits M G Buehler 44 40 10 13 The objective of this work is to develop and experimentally verify advanced device models for a number of failure mechanisms affecting the reliability of semiconductor devices Silicon MOSFET's are susceptible to hot-carrier injection, time-dependent dielectric breakdown, and oxide charging that are due to radiation effects GaAs MESFET's are susceptible to contact degradation and to threshold voltage shifts that are due to viariation in insulator strain Both GaAs and silicon integrated circuits are susceptible to electromigration in the interconnect metallization and to single-event upsets that are due to cosmic rays Models for these and other effects are being developed and incorporated into a transistor-level circuit-simulation code that can be used to verify the performance of highly reliable integrated circuits Si/SiOj Interfacial Research Related to VLSI Technology F J Grunthaner 44 40 10 14 The opportunity exists to prove the technologically relevant S1/S1O2 interface by a variety of surface spectroscopic tools including highresolution x-ray photoemission (XPS) , UV photoemission, secondary ion mass spectrometry, local work-function measurements, and UHV spectroscopic ellipsometry Past efforts in this laboratory have estabhshed the existence of a unique form of S1O2 in the near-interfacial region, and work has begun to examine the presence of silicon suboxides and, therefore, the interfacial microstructure These detailed measurements of the local chemical structure of the S1/S1O2 interface are being correlated with the observed electrical properues of MOS gate oxides, specifically addressing such issues as interface state generation, trapped charge buildup, and time-dependent breakdown The proposed experiments would expand on our bond-straingradient model for radiation effects and would conunue our efforts on the chemical engineering of the oxide/silicon interface Interfacial Studies on Silicide/Silicon Schottky Barriers P J Grunthaner F.J Grunthaner 44 40 10 15 Schottky-barrier formauon at metal/semiconductor interfaces is an important scientific issue that is the subject of considerable effort in compound semiconductors The silicide/sihcon system is considerably less complicated than metal/lIl-V semiconductor systems and offers the possibility of achieving a basic understanding of the fundamental nature of barrier formation Our previous results, based on highresolution XPS analysis of Ni, Pd, and Pt silicide/silicon interfaces, have suggested that the barrier is formed by the presence of a dipole in the interfacial metal-Si bond This analysis is based on unique observauons in core- and valence-level spectra and has suggested 47 Read the entire page →

From page 41...

... pulsars and about fou r years on six newly discovered pulsars The phase measurements are available f o r analysis as geocentric and barycentnc arrival times Raw data records are available as 500- to 1500-pulse integrations fo r durations o f one to three hours This data set was collected using the NASA Deep Space Network facilities at a frequency o f 2295 M H z Other Activities in progress include staUstical studies o f the timing residuals as oudined by Cordes (1980) and an experiment to detect gravitational waves by searching Uming data f o r the effects o f wave-induced perturbations m the Earth-pulsar distance Preprints o f work recently submitted fo r publication are available upon request Reference G S Downs & P E Reichler, Ap J SuppI 53, 169(1983)

Read the entire page →

From page 42...

... urement of Seebeck coefficient, electrical conducUvity, thermal diffusity, and Hall effect are available for these studies Thin-Film Deposition and Device Fabrication for Advanced Electron Devices RJ Stirn 44 40 10 02 Ongoing work at J PL includes exploring the use of chemical vapor deposition, magnetron sputtering, spray pyrolysis, and physical evaporation techniques for the growth of thin-film materials suitable for electron device application Examples of applications are solar cells of higher-conversion efficiency, lowered cost, and improved radiation resistance for space and terrestrial application, GaAs heterostructurs for high-speed low-power FET's and milhmeter-wave devices, and infrared detectors operating in the photovoltaic or photoconductive mode In the area of CVD research, the use of low-pressure and laser photolyic enhancement is of interest in low-temperature deposition and/or improved growth rates and abrupt interfaces between semiconductors Facilities exist for reactive sputter deposition of binary and ternary semiconductors using hydrogen selenide and hydrogen sulfide gases as well Characterizauon facilities available for these investigauons include (1) scanning electron and optical microscopy, x-ray diffraction, EDAX, lon-microprobe, photoluminescence, reflection and transmission spectrophomometry, laser scanning for annealing and/or recrystallization, and (2)

Read the entire page →

From page 43...

... dielectrics with capacitor processing and performance is of particular importance The work involves use of a wide range of quanutauve analytical techniques to assess the thermal, chemical, and structural characteristics of dielectric fluids and polymeric films Wave-Front Propagation N.I Marzwell 44 40 10 05 The physics of high-energy laser systems wave front is analyzed in terms of its diagnosucs, controls, and correction for signal and power transmission through the atmosphere or sea waters Atmospheric transmission and propagation problems attenuate and reduce the quality of the laser energy and limit its applications. To overcome this limitauon, research has been iniuated to understand how laser beams are being impacted with humidity, crosswind, turbulence, slew rate, aperture, and range Methods to optimize the beam quality and to control its poinung accuracy as it propagates through the atmosphere or sea water are being investigated Emphasis is being placed on methods of acuve controls of the optical systems, from controlling a mirror in six degrees of freedom up to systems employing segmented or deformable mirrors that may possess more than 100 degrees of freedom Diagnostic techniques that are being studied include wavefront conjugation and four-wave mixing The purpose of this research is (1)

Read the entire page →

From page 44...

... an autoregressive model to fit the input-output data from the manipulator to achieve higher manipulator-motion accuracies Adaptive Self-Tuning Control of Manipulators in Task-Coordinated System N I Marzwell 44 40 10 07 The dynamic motion of a manipulator is strongly influenced by the mechanical and material properties associated with the manipulator design and environment in which the manipulator is expected to perform Link masses, inertial loadings, joint friction, sensor compliance, link flexibility, and actuator dynamics all couple with load impedance and gravity effects to provide a highly interactive, crosscoupled, nonlinear dynamic system Research is being pursued to address the contro-system design strategies and requirements of dynamic mouon in terms of the changing dynamic configurations, as well as load variability factors Macromolecular Melts and Glasses J Moacanin 44 40 10 08 The equation-of-state (PVT) description of macromolecules in both the melt and glassy states is developed rather well The theory is applicable to single-phase as well as multiphase systems.

Read the entire page →

From page 45...

... Superconductor-Insulator-Superconductor (SIS) Mixer for Submillimeter-Wave Heterodyne Receiver S K Khanna 44 40 10 10 Superconductor-Insulator-Superconductor (SIS)

Read the entire page →

From page 46...

... GaAs and Silicon Transistor-Device Models for Highly Reliable Integrated Circuits M G Buehler 44 40 10 13 The objective of this work is to develop and experimentally verify advanced device models for a number of failure mechanisms affecting the reliability of semiconductor devices Silicon MOSFET's are susceptible to hot-carrier injection, time-dependent dielectric breakdown, and oxide charging that are due to radiation effects GaAs MESFET's are susceptible to contact degradation and to threshold voltage shifts that are due to viariation in insulator strain Both GaAs and silicon integrated circuits are susceptible to electromigration in the interconnect metallization and to single-event upsets that are due to cosmic rays Models for these and other effects are being developed and incorporated into a transistor-level circuit-simulation code that can be used to verify the performance of highly reliable integrated circuits Si/SiOj Interfacial Research Related to VLSI Technology F J Grunthaner 44 40 10 14 The opportunity exists to prove the technologically relevant S1/S1O2 interface by a variety of surface spectroscopic tools including highresolution x-ray photoemission (XPS) , UV photoemission, secondary ion mass spectrometry, local work-function measurements, and UHV spectroscopic ellipsometry Past efforts in this laboratory have estabhshed the existence of a unique form of S1O2 in the near-interfacial region, and work has begun to examine the presence of silicon suboxides and, therefore, the interfacial microstructure These detailed measurements of the local chemical structure of the S1/S1O2 interface are being correlated with the observed electrical properues of MOS gate oxides, specifically addressing such issues as interface state generation, trapped charge buildup, and time-dependent breakdown The proposed experiments would expand on our bond-straingradient model for radiation effects and would conunue our efforts on the chemical engineering of the oxide/silicon interface Interfacial Studies on Silicide/Silicon Schottky Barriers P J Grunthaner F.J Grunthaner 44 40 10 15 Schottky-barrier formauon at metal/semiconductor interfaces is an important scientific issue that is the subject of considerable effort in compound semiconductors The silicide/sihcon system is considerably less complicated than metal/lIl-V semiconductor systems and offers the possibility of achieving a basic understanding of the fundamental nature of barrier formation Our previous results, based on highresolution XPS analysis of Ni, Pd, and Pt silicide/silicon interfaces, have suggested that the barrier is formed by the presence of a dipole in the interfacial metal-Si bond This analysis is based on unique observauons in core- and valence-level spectra and has suggested 47

Read the entire page →

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