AlxGa1-xSb has many problems concerning its growth and process technologies, in spite of its great potential as an optoelectronic material at the near infrared region. This paper describes the technological problems and their solutions on the liquid-phase epitaxial growth of AlxGa1-xSb. The epitaxial layers with smooth surface morphology, whose compositions ranged from x=0.26 to 0.78, were grown by using an improved slide boat which minimized effects of oxygen contamination. The proper growth condition is presented in terms of substrate orientation, cooling rate, and super saturation temperature. Ga inclusions were observed in the vicinity of the interface between the substrate and the epitaxial layer when x>O.5. The p-Al0.26Ga0.74Sb/n-GaSb photodetector was fabricated and its effective photoresponse was shown to cover a range of 0.9μm-1.8μm with a peak at 1.5, μm.
This paper describes some experimental results on the effects of high electric field in relatively thick-oxide MNOS (metal-nitride-oxide-semiconductor) capacitors. The C-V characteristics were measured using a linear-ramp voltage after stressing with a negative bias. The non-steady-state inversion C-V curves exhibit two anomalous phenomena in C, namely, the existence of a minimum attributed to surface generation and a non-equilibrium decrease due to the tunneling of holes into the insulator. Examination with a steady-state I-V (the slopes of the Fowler-Nordheim characteristics) and quasi-static C-V measurements (the stress time dependence of the surface states formation) were added to augment the ramp voltage experiments. The set of results indicates that effects of high electric field on MNOS capacitors are dependent on the Fowler-Nordheim tunneling of ° “ holes ” from Si into Si3N4 via the thick SiO2 layer. The injected holes create hole traps in the SiO2 layer and these traps make holes movable in the SiO2 layer (hopping current).
A laboratory type cesium beam frequency standard is being developed for experimental use as a primary standard at the Radio Research Laboratories of Japan. The Ramsey cavity interaction length is about 50cm and the expected accuracy is a few parts in 1013. The short-term stability predicted from beam measurement is 3×10-12/τ1/2. In this paper a squarewave frequency modulation digital servo is proposed as the electronic circuitfor the beam tube. Results of theoretical and experimental investigation are presented. The results show that the servo system noise is 2×10-10/τand a transfer function model for the analysis of its fre-quency stability is useful.
The movable capillary tube viscometer, herereported, is composed of a capillary tube, its ends being connected flexibly by two bellows to fixed reservoirs and a differential transformer. The elastic force exerted by the bellows is measured by the differential transformer. The results of experiments show that the values of viscosity obtained by the trial movablecapillary tube viscometer agree fairly well with those by the ordinary capillaryviscometer of pressure different type. The movable capillary tube viscometer is considered to be applicable to automatic control because of its simple construction and of the fact that an electric voltage proportional to the viscosity is obtained continuously
A microcomputer-controlled wave-forming device was made to undulate soft ground. With the use of this device soft ground was undulated into a number of sine waves with different wave lengths but constant amplitude. The rolling resistance of wheels on such undulated soft grounds was measured-with an apparatus to measure the rolling resistance of the wheel and a data processing system. The averaged driving torque and tractive force attain to maximum values, when the crest part of the road surfaces has the same radius of curvature as that of the wheel. These values approach gradually to those of flat surface running as the wave length becomes longer. It was found that when the wave length becomes very short, the values of the averaged driving torque and tractive force become even smaller than the values on a flat surface.
An attempt has been made to establish a practical dry development procedure for submicron pattern lithography in LSI fabrication process with RF discharge plasma under low gas pressure. Poly methyl iso-propenyl keton resist film containing 4, 4'-diazidoe diphenyl ether on a silicon wafer was etched in oxygen plasma at 1.0 torr, 13.56 MHz and 100 W RF power during a few minutes after exposure to deep UV rays through a chrominum mask and heating at 140°C for 30 minutes.
A sludgy emulsion obtaind by rubbing mechanically a surface of Pt-Rh alloy with an aqueous suspension of alumina was found composed of alloy and alumina particles of about 50 Å in size. This emulsion turned out to be usable as a contact catalyst for slow combustion of benzine vapor.
The study of sound wave propagation properties in liquid crystals has provided a useful knowledge on the hydrodynamic and elastic behaviours of these systems, which enables us to test the continuum theories about these systems. It also has provided a considerable contribu-tion to the investigation of unique phase transition behaviours shown by liquid crystals. In this paper, longitudinal and shear wave propagation properties in nematic and smectic A liquid crystals and near the nematic-isotropic and the smectic A-nematic phase transition points are briefly reviewed by comparing the experimental results with the existing phenomenological theories of these systems.
Present status of reserches on tritium technology for fusion reactor is reviewed. Since some expriments on permeability of tritium through various metals and alloys have been carried out, the reported values of permeability which are usefu for evaluating the release of tritium from containment system are summerized. Initial tritium inventory in fusion reactor might be supplied from heavy waterin heavy water-moderated reactor, spent fuel in reprocessing plant and neutron-irradiated lithium com-pounds in fission reactor.