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Notes: The physical and electrical characteristics of gallium (Ga) ion implanted 〈100〉 silicon, annealed for times of the order of seconds to several tens of seconds for temperatures in the range of 550–900 °C, are presented. It is shown that for the chosen doses of 1–6×1015/cm2 and energy of 100 keV highly electrically active p-type layers (approaching 100%) can be achieved. The highest activation being reached at temperatures below ∼650 °C with no profile distortion. For temperatures in excess of 800 °C this electrical activation decreases and significant profile movement occurs even for times as short as 2 s.

Notes: Recent investigations of ohmic contacts to silicon indicate that for many metallization candidates, contacts made to p+Si are of considerably higher resistance than similar contacts to n+Si. Recent studies have also shown that active boron acceptors in silicon may be deactivated by hydrogen. We discuss the effect that this hydrogen deactivation may have on the specific contact resistance, in view of the results of recent studies that involved several different metallizations. We propose means to deal with the problem in order to secure good ohmic contact characteristics to both polarities of active regions in silicon.

Notes: We study the issue of reflectivity in interactions of laser beams with condensed matter substrates. In particular, we discuss the effect that the reflectivity has on the melting of silicon. The theory of the laser-solid interaction expresses the properties of the hot zone that forms in the solid in terms of the beam parameters, such as the power and the spatial profile. The value of the reflectivity determines the actual value of the deposited power, and hence greatly influences the properties of the hot zone. The reflectivity is temperature dependent, and hence it constantly varies during the period in which the laser power rises to its maximum value. Therefore, a meaningful model is required in order to properly account for its effects. We have developed such a dynamical model for the reflectivity. The results of this model compare well with relevant experimental measurements.

Notes: Boron diffusion in ion-implanted and annealed single-crystal and amorphized Si is compared to determine the effect of amorphization on the initial transient boron motion reported for single crystal. The boron was implanted at 20 keV and at doses of 1×1015 and 3×1015cm−2. The Si was either preamorphized or postamorphized to a depth of 320 nm by implantation of Si ions at three different energies. In the amorphized samples the entire boron profile was always contained within this distance. The samples were annealed by furnace or rapid thermal annealing to 900–1100 °C with or without a preanneal at 600 °C. The initial rapid diffusion transient in the tail region of the boron profile was observed in all the crystal samples. This transient was totally absent in the amorphized samples. This is manifest by careful comparison of boron concentration profiles determined by secondary ion mass spectrometry of single-crystal and amorphized samples after annealing. For anneals where significant motion occurs, the profiles of the amorphized samples could be fit with a computational model that did not include anomalous transient effects. It is proposed that excess interstitials cause the transient diffusion in the case of the crystalline samples. The source of interstitials is believed to be provided by the thermal dissolution of small clusters that are formed by the implantation process. They exist for only a short time, during which they enhance the boron diffusion. Since there is no enhanced diffusion in the amorphous region that regrows to single crystal, apparently interstitial clusters are neither produced by nor do they survive the regrowth process in that region. In addition, the interstitials generated by the damage beyond the amorphous-crystalline boundary are prevented from entering the regrown region by the dislocation loops formed at that boundary which act as a sink consuming the interstitials diffusing toward the surface.

Notes: Hydrogenated amorphous silicon with different levels of phosphorous doping has been deposited by plasma-enhanced chemical vapor deposition at a temperature of 125 °C. Its electrical properties are largely inferior to those of standard material grown at 275 °C, but they can be improved by a rapid thermal annealing process. The change in electrical conductivity depends on the doping level and is better for 0.1% than 1% or undoped samples. In this case the electrical conductivity, after annealing, increases by three orders of magnitude and is only a factor of 10 less than that of the best conducting material produced at 275 °C. The improvement in electrical properties is not causatively related to the loss of hydrogen. This low-temperature material, after annealing, forms relatively low resistance contacts with molybdenum or aluminum and is suitable for application in thin-film transistor technology.

Notes: Abstract— (1) Mouse cerebrum slices swell in tris-buffered Krebs-Ringer medium. Swelling is rapid at first, then slows to a more or less constant rate. Even after 3 hr incubation, water content/g of tissue dry wt. shows no sign of an asymptotic limit. Swelling is the same at 37° and at 0°.(2) Tissue water measured by incubation with tritiated water is equal to total tissue water measured by drying slices. Equilibration between tritiated water and tissue water is complete within 2 min.(3) Tissue liquid can be divided into three phenomenologically distinguishable compartments: first inulin space, which is the compartment permeable to inulin at both 0° and 37°; second inulin space, which is the compartment permeable to inulin at 37° but not at 0°; and 37°non-inulin space, which is the compartment impermeable to inulin at both 0° and 37°. The evidence for this is:(a) Penetration of inulin into tissue is greater at 37° than at 0°. After the first 20 min the rate of penetration at 0° is approximately equal to the rate of penetration at 37°, and only slightly less than the rate of increase of total tissue water. Therefore the smaller inulin space observed at 0° cannot be due to slower entry of inulin.(b) The inulin content of slices incubated in inulin-containing medium at 37° and cooled to 0° in the same medium is the same as the inulin content of tissue incubated at 37° without subsequent cooling. In contrast, the inulin content of tissues preincubated in inulin-free medium at 37° and then incubated in inulin-containing medium at 0° is the same as the inulin content of tissues incubated in inulin-containing medium at 0° without preincubation at 37°. Therefore the smaller inulin space at 0° than at 37°can be due neither to a reversible temperature-dependent change in the size of one single inulin space nor to an irreversible, greater swelling of a single inulin space at the higher temperature, but is due to some portion of the 37° inulin space becoming impermeable to inulin at 0°.(c) Some inulin is retained by tissue incubated with inulin at 37°, then transferred to inulin-free medium at 0°; the amount of retained inulin is equal to the difference between inulin content of tissue incubated with inulin at 37° and tissue incubated with inulin at 0°. This confirms 3b above and in addition shows that inulin which has entered the second inulin space at 37° is trapped there when this space becomes impermeable to inulin at 0°.(4) The penetration of the amino acids, L-lysine and D-glutamate at 0° is equal to the penetration of inulin at 37°. This confirms the real existence of the 37° inulin space at 0°, and shows that the barrier at 0° between the first and second inulin spaces does not exist for these substances.(5) The amino acids L-leucine and glycine penetrate total tissue water at 0°. L-leucine is actively transported at this temperature.(6) The amino acids α-aminoisobutyric acid, L-leucine, and L-lysine at 2 mm have no effect at 37° on either the inulin space or the non-inulin space.(7) The inulin space is insensitive at 37° to physiologically significant changes in the medium. In contrast, the non-inulin space is quite sensitive to these changes. Addition of D-glutamate greatly increases the non-inulin space; addition of ouabain or cyanide, or omission of glucose, increases the non-inulin space slightly; and replacement of Na+ ion by choline+ ion greatly decreases this space. These changes are independent and roughly additive.

Notes: A Bragg x-ray spectrometer of high spectral resolution (λ/Δλ=10 000–20 000) which accommodates three crystals and position-sensitive detectors in the Johann configuration has been installed in the diagnostic basement of the tokamak fusion test reactor (TFTR) for the measurement of radial ion temperature profiles. The ion temperature is derived from the Doppler broadening of Kα-resonance lines of metal impurity ions, e.g., Ti, Cr, Fe, and Ni, in the helium-like and hydrogen-like charge states. The x-ray diffraction plane is almost perpendicular to the magnetic axis, but slightly tilted by an angle of 3.8°, which makes it possible to measure poloidal and toroidal plasma rotation velocities of vaitch-theta〉5×103 m/s and vΦ〉1×105 m/s, from the Doppler shift of spectral lines. Results obtained from the observation of TiXXl Kα-line spectra with a 220-silicon crystal of a 2d spacing of 3.8400 A(ring) and a curvature radius of 11.05 m are reported.

Notes: Four groups, Young Males, Young Females, Aged Males and Aged Females, were run in a discrimination conditioning paradigm with a variety of autonomic and central measures. This paper deals primarily with Electro-Dermal Responses. The findings indicate that in all measures the Young Males and Young Females show the best discriminated conditioning, followed by Aged Females and Aged Males.In the GSP there are hints that the negative wave of the response might be related to the orienting phenomena whereas the positive wave is what becomes discriminately conditioned in the experiment.A cognitive questionnaire was accurately answered in the same rank order as the conditioning, that is. Young Males, Young Females, Aged Females and Aged Males.