Silicon on sapphire (SOS) is subjected to a large lateral compressive strain (_??_4×10-3) due to the thermal expansion coefficient difference between silicon and sapphire. In this paper, electrical properties of SOS influencd by this strain through the change of the band structure are reviewed. In the conduction band of (001) SOS, the energy of kz valley is raised by _??_60 meV relative to those of kx and ky valleys, which reduces the electron mobility and produces elastoresistance and magnetoresistance anisotropies different from those for bulk n-type silicon. The compressive strain splits the quartet state J=3/2 at the top of the valence band into mJ=±3/2 and mJ=±1/2 states. Room-temperature magnetoresistance anisotropy of p-type (001) SOS and p-channel MOS Hall mobility which exceeds n-channel one below _??_130 K may be interpreted by the upper, anisotropic and non-parabolic mJ=±3/2 band.
Spectral absorption line profiles of Ca and Ba in shock heated Ar at about 4000°K have been measured by means of a MOS-type image sensor. From simulations measurements of total absorption and hook separation, damping constants and effective cross-sections for broadening of the resonance lines of Ca and Ba by Ar are determined. Van der Waals interaction constants between Ar and Ca/Ba are also calculated.
A theory based on Stokes's law together with the assumption of a quasi-steady state of liquid flow is presented for the determination of the coefficient of viscosity η in a lifting liquid type viscometer. The theoretical work shows that the coefficient of viscosity η* calculated by Stokes's law depends on the lifting velocity and that its limitting value when the velocity becomes zero is the true value η of the coefficient of viscosity. The apparatus used in the experiments is composed of a spherical plastic ball hung on one arm of an automatic balance and a vessel which can be lifted with approximately constant acceleration by cylindrical cam mechanism. The liquid to be examined is put in the vessel and the ball is immersed in the liquid. The apparent mass of the plastic ball in the liquid depends on the lifting velocity of the vessel with the liquid in it. By measuring the decrease of the apparent mass of the ball, the viscous drag ƒ acting on the ball is determined. The agreement between the theoretical and experimental results is generally good and it is recognized that the above mentioned theory provides a basis for the theoretical work in this field.
An oscillation phenomenon has been conspicuously noticeable in sintered SnO2 incorporated with Pd, when exposed to CO gas at 200°C of the sample temperature. The addition of ThO2as a catalyst and hydrophobic silica as a binder enhances the phenomenon and increases its stability. The oscillation frequency and amplitude depend upon the CO gas concentration the sample temperature and the silica contents. The dependence of the frequency on the concentration of silica involved in the samples is apparently similar to that on the sample temperature. A fundamental mechanism of the enbanced oscillation is discussed on the basis of the redox process occurring at the induced active sites from increasing temperature or increasing silica contents.
The previous experimental result that the escape length of photoelectrons in cobalt stearate monomolecular multi-layers increased with emission angle was examined by a Monte Carlo simulation. The simulated result agreed with the experimental one. The increase of escape length with emission angle appeared notably for low energy electrons. The escape length of 500 eV-electrons at the emission angle of 50° was about 1.2 times of that at the emission angle of 0°, while no increase appeared for 1500eV-electrons in the range of emission angle from 0° to 50. It was revealed that the dependence of escape length on emission angle was due to the elastic scattering of electrons in the absorber layer. In the case of 500eV-electrons, the escape length at the emission angle of 0° was about 0.8 times the inelastic mean free path.
In an attempt to obtain rapidly the energy distribution curve of electrons in plasmas, a new method of differentiation using delay elements is developed. To check the utility of the method, an apparatus based on the method was built and some experiments were carried out, which showed that the energy resolution could be increased up to 0.02eV in a rapid scan of the order of one second. In the present paper, first the principle of the delay line differentiator is given and next _??_ comparison is made between the present differentiator and the conventional ones. Merits of the delay line differentiator are made clear from the view point of frequency response of the circuit and the frequency spectrum of the probe characteristic. Finally, it is shown that the energy distribution curve obtained by the present method is superior to that by the usual alternating current method.
Solid state WO3 electrochromic cells were fabricated using LiI as the solid electrolyte. Good contrast and response time below 1 sec have been observed for 5 V application at room temperature. In the cell structure, WO3, LiI and SiO are successively evapprated onto a NESA glass substrate. Another NESA glass, used for the counter electrode, is pressed down on it. Since Lii is a Li+ion conductor, the lithium ions seem to contribute to the coloring and bleaching processes.
The molecular processes underlying the taste reception have been interpreted on the basis of physical chemistry. The followings are key points of the physicochemical mechanism of taste reception: 1) The change in membrane potential of taste cell mainly stems from the change of the surface potential instead of the change in ion permeability of the membrane. 2) The initial process of taste reception is the adsorption of stimulus chemicals on the membrane surface. 3) The adsorption of chemicals causes a conformational change in the structure of receptive membrane, which in turn induces a change of the potential at the membrane-solution interface. 4) The labile structure as well as the fluidity of chemoreceptive membranes are characteristics of the sensitive functional membranes in living state. Taking these characteristics of state cell membranes, some chemical sensors which respond specifically and sensitively to certain reagents have been developed.
semi-conductor devie assembly process is composed of die-bonding and wire-bonding operatios. This process involves a lot of manual operations using microscopes. Automation of this process involves a lot of manual operations using microscopes. Automation of this process has been desired for cost reduction, quality stabilization etc. This paper describes the problem and prospects of bonding technique, the fully automated die-bonding machine, and the fully automated wire-bonding machine by introducing the pattern recognition technique which we have newly developed.
Among many factors which influence the reliability of plastic encapsulated semiconductor devices, the most important is the existence of impurities and water vapor in plastic encapsulants and as a consequence their influence has been the subject of several investigators. The work reported in this paper concerns the effect of impurities and water vaper on the reliability of semiconductor devices. At first, the level of impurities and water vapor in plastic encapsulants are described. Then the mechanism of metallization corrosion especially impurities induced electrochemical reaction of aluminum is discussed. Electrical degradation of devices is also described and the correlation between the time to failure of devices and environmental conditions is discussed. The method of protection against the influence of impurities on the degradation of semiconductor devices is shown. Among them, coating the chip with some specific polymers is effective for the reliability improvement of plastic encapsulated semiconductor components.