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Removed from the deposition region, an upstream hydrogen microwave plasma generates arsenic hydrides by etching the surface of solid arsenic. The hydrides are transported to the deposition region and mixed with trimethylgallium to achieve low temperature (350°-400°C) and low pressure (750 mtorr) homoepitaxial GaAs films. Low precursor V:III ratios are used to achieve homoepitaxial films with high levels of carbon dopants (l019 to mid 1020 cm−3). No active or afterglow plasma exists in the growth region. The observed homo epitaxial growth activation energies of 54 kcal/mole and 66 kcal/mole for films deposited with V:III ratios of 1:1 and 1:4, respectively, are in the range of those reported for the heterogeneous decomposition of trimethylgallium in the absence of arsine. The films are found to be of good crystalline quality via double crystal x-ray rocking curves. The majority carriers are holes and have hole concentrations that correlate to the carbon doping, as determined by room temperature Hall effect measurements and secondary ion mass spectroscopy. Carrier mobility versus carbon concentration is also presented.

Electrical transport properties of zone‐melt‐recrystallized Si films of Si‐on‐Insulator wafers were investigated using resistivity and Hall effect measurements between 77 and 300 K. Both graphite strip and cold cathode electron beam methods were used for zone melting which produced high resistivity (≳103 Ω cm at room temperature) recrystallized films. Phosphorus implantation into the silicon films to a dopant level of 1×1016 cm−3 and subsequent annealing at 1100 °C reduced the room‐temperature resistivities to ∼1 Ω cm. Hall mobilities of 950 cm2/V s were observed at room temperature for both materials after the implant anneal sequence. However, for temperatures less than 150 K, the mobility is higher in graphite strip than in electron beam recrystallized films. This behavior is consistent with the relative crystalline qualities of the two films as determined by electron channeling and x‐ray diffraction. It is noteworthy that a deep level was observed at 0.2 eV below the conduction band in the graphite str...

A downstream near afterglow plasma was used to deposit epitaxial GaAs at substrate temperatures as low as 300 °C. Feedstock organometallics of trimethylgallium and trimethylarsenic were employed at a ratio of 1:2, respectively. The observed growth rate varies with the substrate temperature, but no growth occurs without the plasma. Scanning electron microscopy electron backscattering was used to probe the single crystal quality of the deposited layers.

In classical hydrodynamics, a Magnus force exists between a vortex and the hosting fluid acting transverse to their relative motion. There is a quantum Magnus force acting on vortices in superfluids and superconductors and an analogous force acting on magnetic vortices excited in spin systems. Couplings with the system quasiparticles can modify this to an effective Magnus force by introducing transverse damping forces. The existence and magnitude of transverse damping forces are highly controversial and have not been settled by experiment. We derive the various damping forces on a vortex in a magnetic system, in particular, damping forces acting longitudinally and transversely to current and past motion (memory effects). In a magnetic system, we expect experiments can more accurately study vortex motion for comparison with theory. Despite the simplicity of the spin system, the results are general and should reveal quantitative behaviour for the superfluid/superconductor systems.

Under circumstances in Zone-Melt-Recrystallization (ZMR) of Si-on-Insulator (SOI) structures where radiative heat loss is significant, the ∼50% decrease in emissivity when Si melts destabilizes the Si molten zone. We have demonstrated this both experimentally using a slowly scanned e-beam line source and numerically with a finite-element computational simulation. The resulting instability narrows the process window and tightens requirements on beam control and background heating uniformity, both for e-beam ZMR systems and optically-coupled systems such as a graphite strip heater.

Publisher Summary This chapter discusses recent progress in the application of photon beams and electron beams to semiconductor device fabrication. Specifically, it examines photon and electron beam assisted chemical vapor deposition (CVD) of microelectronic films, electron beam induced annealing of ion implantation damage and associated dopant activation. It also examines electron beam induced alloying of silicide structures, self-developing electron beam proximity lithography of submicron features and traveling-melt photon, and electron beam recrystallization of deposited polycrystalline silicon films on SiO2. Thermal CVD relies on high substrate temperatures and catalytic reactions between donor molecules and substrate surfaces to achieve the dissociation of feedstock gases with binding energies in the 1 to 3 eV range. One improvement over conventional thermal CVD techniques is plasma-enhanced chemical vapor deposition (PECVD). The chapter compares laser and electron beam induced traveling-melt recrystallization of polysilicon deposited on four inch wafers. This purely thermal process consists of locally melting an area of the deposited polysilicon film followed by propagation of this melt front across the entire wafer surface.

In situ generated arsenic hydrides are reacted downstream with trimethylgallium (TMGa), both in the presence of and in the absence of a downstream hydrogen afterglow plasma. The homoepitaxial activation energy dramatically changes from 62 kcal/mol for the pure thermal to 21 kcal/mol for the plasma‐assisted growth. The carbon incorporation mechanism for the plasma‐assisted growth at temperatures less than 400 °C has a distinct activation energy for carbon incorporation of 23 kcal/mol, independent of V‐III ratios. At temperatures above 400 °C, the level of carbon incorporated in the films reaches a level that appears to be dependent on the gas‐phase precursor V‐III ratio. The activation energy of the low‐temperature region is consistent with the surface decomposition of arsenic hydrides.

Removed from the deposition region, an upstream hydrogen microwave plasma etches a surface of solid arsenic located downstream to generate arsenic hydrides. The latter are used with trimethylgallium (TMGa) to achieve low temperature (400–490° C) and low pressure (750 mTorr) homoepitaxial GaAs films. No active or afterglow plasma exists in the growth region. The homoepitaxial growth activation energy of 62 kcal/mole is consistent with the heterogeneous decomposition of TMGa in the absence of arsine. Precursor V-III ratios as low as 0.25 are used to achieve homoepitaxial films, but with high levels of carbon impurities (1019 to mid 1020 cm−3). Carbon incorporation increases at low V-III ratios (0.25 to 0.5) for increasing temperatures with an activation energy of 23 kcal/mole. As the V-III ratios are increased above 1.0, the carbon incorporation activation energy decreases slightly to 15 kcal/mole.

Removed from the deposition region, an upstream hydrogen microwave plasma generates arsenic hydrides by etching the surface of solid arsenic. The hydrides are transported to the deposition region and mixed with trimethylgallium to achieve low temperature (350–400 °C) and low pressure (750 mTorr) homoepitaxial GaAs films. Low precursor V/III ratios are used to achieve homoepitaxial films with high levels of carbon dopants (1019 to mid 1020 cm−3). No active or afterglow plasma exists in the growth region. The observed homoepitaxial growth activation energies of 54 kcal/mole and 66 kcal/mole for films deposited with V/III ratios of 1/1 and 1/4, respectively, are in the range of those reported for the heterogeneous decomposition of trimethylgallium in the absence of arsine. The majority carriers are holes and have hole concentrations which correlate to the carbon doping, as determined by room temperature Hall effect measurements and secondary ion mass spectroscopy. Carrier mobility versus carbon concentration...

A spatially confined disk shaped hydrogen plasma is used for plasma assisted organometallic vapor phase epitaxy (PAOMVPE) of GaAs at substrate temperatures from 245–430°C. Feedstock gases, trimethylgallium (TMGa) and trimethylarsenic (TMAs), are introduced downstream from the disk shaped plasma in the near afterglow. Dissociation of the organometallics is dominated by VUV photons and metastable species energy transfer reactions rather than non-selective electron impact. At the temperatures employed no thermal CVD occurs. An Arrhenius plot of the growth rate shows a low activation of 3 Kcal/mole for surface mobility. The transitional temperature from amorphous to homoepitaxial growth (300°C) is determined via electron diffraction patterns from deposited films versus substrate temperature. Increases in the feedstock gas V-III ratio resulted in decreases in absolute carbon concentration in the deposited films.

Composition-dependent optical and electrical properties of L-CVD (Al2O3)1-c-(AlN)c composite films are examined. The optical properties exhibit a continuous change from Al2O3 to AlN with increasing value of the composition parameter c from zero to one. There is a critical concentration value of about 0.3 below and above which Al2O3- and AlN-like optical properties are observed. The impurity absorption regions are 5.1-6.7 eV for Al2O32 and 4.6-6.0 for AlN, while the energy gap is about 6.7 eV for Al2O3 and 6.0 eV for AlN. The electrical properties of Al-insulator n-Si MIS structures display externally programmable states when bulk-controlled electron emission occurs from the traps. In the high-field region a persistent polarization field is established within the insulator. C-V characteristics of the samples are more sensitive to the concentration factor c than the I-V characteristics. A large clockwise hysteresis is observed for AlN, but a smaller counterclockwise one is observed for Al2O3.

The electron beam assisted chemical vapor deposition of silicon nitride anti-reflection coatings onto thin film CdS/CuInSe2 solar cells and the resultant effects on their performance are reported. In some cases large increases in the short circuit current open circuit voltage and fill factor were observed. The present results are explained by the usual index matching anti-reflection mechanisms and either the passivation of undesirable shunts or improvement of intrinsic diode characteristics.

We have demonstrated electron beam assisted chemical vapor deposition of silicon dioxide films on silicon substrates via electron impact dissociation of SiH4 and N2O gas. Dissociation of reactant gases occurs primarily in the confined planar region of the electron beam created plasma. Electron beam deposited SiO2 films have been categorized in terms of their electrical, physical, and chemical properties.

Silicon nitride films have been deposited using an electron beam created plasma in a silane, ammonia, and nitrogen mixture. The films were deposited at substrate temperatures between 50 and 400 °C. Physical, chemical, and electrical properties of these films are reported.

With 120 minutes of pneumatic tourniquet application to the distal extremity in the horse, the following effects were noted in the tourniqueted limb vein (TLV): (i) local venous acidemia, (ii) increase in serum K+ concentrations, (iii) minimal changes in plasma total solids, Na+, or osmolality, and (iv) apparent reduction in hematocrit values when compared with the same measurements in the control leg. Tourniquet release after 120 minutes produced a prompt return to base line for PCV and PO2 in the TLV; however, pH, PCO2 and K+ values in the TLV required 10 to 15 minutes to reach base line (TLV or control leg vein).

A glow discharge electron beam has been used to deposit silicon dioxide (Si0 2 ) and silicon nitride (Si 3 N 4 ) films for microelectronic applications. Electron beam assisted CVD is a new technique in which the reaction volume is defined mainly by the geometry of the electron beam and offers the possibility of uniform deposition over large areas. The Si0 2 films were deposited in silane-nitrous oxide-nitrogen mixtures, and the Si 3 N 4 films were deposited in silane-ammonia-nitrogen mixtures. The films were deposited with a 2-4 kV electron beam parallel to the sample, at 0.1-1 Torr pressures, and at substrate temperatures from 50-400°C. The index of refraction, sthoichiometry, pinhole density, etch rate, conformal step coverage, and hydrogen bonding were measured.

Evidence of cerebrovascular disease at autopsy was compared in 2 groups of men: 186 long-time residents of Hiroshima, Japan, and 253 men of Japanese ancestry long resident in Honolulu, Hawaii. They were 45 to 71 years-of-age at death. Atherosclerosis of the circle of Willis and its major branches, sclerosis of the intraparenchymal arteries and the frequency of cerebral hemorrhage and cerebral infarct were compared in the 2 populations. The Honolulu subjects had significantly more atherosclerosis of the circle of Willis, but less intraparenchymal artery sclerosis and less cerebral infarction. Cerebral hemorrhage was equally frequent in the 2 cities. It was concluded that cerebral infarction is more frequent in Japanese men in Hiroshima than Honolulu, and that men of Japanese ancestry in Honolulu are spared an appreciable risk of cerebral infarction through decreased frequency of intraparenchymal arterial sclerosis despite higher levels of atherosclerosis of large intracranial arteries.

Ninety-five patients were examined between the ages of 25 and 74 years of age at the Tuscaloosa Veterans Administration Hospital and the University of Alabama at Birmingham School of Optometry. Of the 95 patients 54.7% had never taken chlorpromazine and 45.3% were taking chlorpromazine. We analyzed the prevalence of ocular side effects of chlorpromazine and found that the most prevalent side effect was anterior lens capsule dusting followed by corneal stromal pigment dusting. Both of these changes occurred at a lower cumulative dosage level than had previously been reported. The prevalence of anterior corneal epithelial opacification, anterior corneal staining, cataracts, and pigment in the macula is also reported.

The properties of SiO2 and Si3 N4 films deposited by an ArF excimer laser, glow discharge electron beam and conventional plasma-enhanced CVD are compared. The deposition apparatus, technique, and conditions in addition to the physical, chemical and electrical properties of the films are discussed.

An ArF excimer laser was used to photochemically deposit thin films of silicon dioxide, silicon nitride, aluminum oxide and zinc oxide at low temperatures (100-500°C) for microelectronic applications. High depo-sition (>1000 A/Min) rates and conformal step coverage were obtained. The hydrogen bonding, pinhole density, index of refraction, etch rate, and breakdown voltage have been measured for the Si02 and silicon nitride films. The effect of substrate temperature and ArF (193 nm) surface photons on the physical, chemical and electrical properties of Si02 films have been investigated.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Recrystallization of silicon-on-insulator (SOI) films using a line-source electron beam is described. This unique heat source can continuously emit several kilowatts of - 5 keV electrons into a beam 150 mm in length and - 2.5 mm in width, an exposure area which allows processing of 100 mm substrates in a single pass. An attractive aspect of this beam is the ability to control the beam profile, which in turn allows one to influence the thermal gradients present during recrystallization. Using a tightly focussed beam to recrystallize the SOI layer results in a film whose physical properties are generally attributed to films grown with a high thermal gradient at the solidifying liquid-solid interface (highly branched subboundaries with a maximum spacing of - 20 microns and several degrees of angular mismatch.) By reducing the gradient at the growth interface it is possible to achieve unbranched sub-boundaries with over 70 micron spacing and less than 0.5 degrees of out-of-plane tilt misalignment.

Here we report on the electrical properties of laser-assisted chemical vapor deposited (CVD) aluminum oxynitride (AION) films on InP substrates for use as metal–insulator–semiconductor (MIS) diodes. From previous investigations, the major problems associated with InP MIS devices related to current drift phenomena and interfacial instabilities. These instabilities depend on surface preparation and surface damage induced during insulator deposition. Laser-assisted CVD may provide a less radiation damaging deposition technique, and thus InP MIS devices may be improved.

o-Vinyl-phenole (I) und Salicylaldehyde (II) konnen zu den Dibenzodioxoeinen (III) kondensiert werden; aus den beiden Verbindungen (IIIa) und (IIIb) erhalt man bei der katalytischen Hydrierung die 2,2′-Trimethylendiphenole (IV).

D URING the last ten years numerous industrial surveys have been made by the U. S. Public Health Service. In the course of these surveys, approximately 10,000 general physical examinations were made of male workers and approximately 2,000 of female workers. We fully realize the difficulties of interpreting general physical examinations, especially when they cover a long period and are made by several different physicians. Knowledge of industrial hazards is derived chiefly by study of a specific problem through methods carefully chosen with that definite purpose in mind. None the less, in view of the large numbers involved and the almost complete absence in the literature of data on physical or physiological measurements of industrial workers in this country, it seemed worth while to determine what information could be secured by a statistical analysis of these general examination records. The results of the examinations in the garment and pottery industries have already been published.1