The phosphorus concentration, chemical structure of phosphorus, etching rate and the density of the SiO2 films deposited by rf-sputtering using P2O5-SiO2 sintered target were studied. And the gettering effect of mobile ionic charge for this film was also investigated. It was found that the phosphorus concentration depended strongly on the distance between the target and the substrate (dT-S) in the case of low power density sputtering, i.e. it increased with an increase of dT-S, but it decreased slightly in the case of high power sputtering. Furthermore, the effect of mobile ionic charge gettering was clearly observed in the SiO2 film deposited by this method. And the value of 5 5×109cm-2 was obtained as the mobile ionic charge density in a phosphorus concentration of 1×1021cm-3.
The components of the measuring instrument used for the present investigation are explained, and, using this second derivative gradiometer type SQUID magnetometer, studies on the fetal magnetocardiogram and on the magnetocardiogram in the normal controls and of patients with various cardiac diseases were carried out in a magnetically unshielded environ-ment. In these studies the simultaneous recordings of MCGs and ECGs were always taken at the same precordial chest position V1 to V6. From the observation of MCGs in these studies, we obtained many more perspicuous informations useful for clinical diagnosis than from ECG. As to the MCGs in the patients with anterior myocardial infarction, we have observed 2 kinds of characteristic changes in MCGs pattern and this fact was demonstrated by an experiment using dogs. Further, in the MCGs from a patient with complete A-V block we have found a secondary atrio-ventricular pace-maker spike which might be related with the ventricular depolarization.
An interferometric dilatometer using a He-Ne laser has been developed. In order to measure the thermal expansion coefficient of different shapes of specimens, three kinds of specimen holders have been designed and compared with each other experimentally. The primary factors which affect the accuracy of the thermal expansion coefficient are discussed quantitatively and it is revealed that the thermal expansion coefficients of ordinary materials can be estimated with an accuracy of better than ±1%. Thermal expansion coefficients of copper specimen in the neighborhood of the room temperature were measured. The copper specimens used in the experiment were made of both the standard reference material 736, supplied by the National Bureau of Standards (USA), and ordinary materials in commercial use. The thermal expansion coefficient of SRM 736 measured here was compared with other results and it is confirmed that the difference between present data and others are less than 0.7%.
The accurate thermoelectric resistance thermometer reported in this paper is a graft thermometer composed of a thermocouple and a resistance thermometer, and it enables us to measure accurately the melting points of pure substances. The temperature of the grafting portion is so controlled to be as nearly equal to a preset temperature as possible. It is known theoretically that the graft temperature need not be kept constant, but a slow change within a certain small temperature range is allowable. Experiments were carried out to measure the melting points of three pure substances (Tin, Lead and Benzil). The results of experiments show that the melting points are measured with tolerable accuracy by the trial accurate graft thermometer.
A method is described to measure a surface state distribution and a minority carrier generation rate in MOS systems by using the Deep Level Transient Spectroscopy (DLTS). First, the capacitance transient of a MOS diode is analyzed and a formula is presented to characterize a DLTS spectrum. Then, measurement conditions are discussed to separate a DLTS component resulted from carrier emission and that from minority carrier generation and some examples of experimental results are presented. It is also reviewed how to determine energy and temperature dependencies of capture cross sections at surface states. The features of this method are compared with the conventional C-V methods.
Effects of oxygen impurity in Czochralski silicon substrates on MOS device performance were investigated by using wafers with various oxygen concentrations. The wafers were prepared by newly developed oxygen concentration control technique. Thermally induced defect density is strongly dependent on oxygen concentration. Degradation in device character-istics due to these defects is shown. Wafer warpage, implant damage and intrinsic gettering effects were examined. 256 kbit MOS RAM has been realized by using wafers with oxygen concentration 8×1017 atoms/cm3. Present status of researches is reviewed.
Effects of the spontaneous emission in the semiconductor injection lasers are reviewed and discussed. This effect influences to the laser operation in various aspects. The difinition and derivation of spontaneous emission factor are given followed by the measuring method. In the conventional injection lasers, the spontaneous emission factors are evaluated to be between 10-5 to 10-6. The effects of spontaneous emission to the lasing properties are discussed related with identification of the threshold current, the lasing spectral width, the single longitudinal mode condition, and the influence to the direct modulation. The effects of spontaneous emission discussed above is essentially common to other lasers.
Several experiments of crystal growth in space are reviewed. Physical meaning and problems of these experiments are discussed. The future programme for single crystal growth using space shuttles is described.
The utility of ternary chalcopyrite compounds for the second and third harmonic generation of the CO2 laser frequency has been reviewed. By comparing the linear and nonlinear optical properties of AgGaS2, AgGaSe2, and CdGeAs2 for these frequency conversion processes, AgGaSe2 has been found to be superior to the other crystals for the repetitively Q-switched high-average-power CO2 laser due to its higher transmission at the interacted frequencies and larger angular acceptance angle.