Department of Electronic Mechanical Engineering, Faculty of Engineering, Nagoya University Observations of semiconductor devices were made by the secondary electron image mode of the low voltage SEM. It was found that there exist appropriate imaging conditions under which the passivation surface of devices can be imaged without charging disturbances. Under the same conditions a method was proposed of inspecting the voltage profile of the circuits underneath the passivation by detecting the reversible contrast variations discovered in the present work, Systematic investigations were made to find out factors which affect the reliability of the method. Finally, anomalous surface layer model was concisely described to provide a consistent interpretation for the contrast mechanism.
Wave propagation phenomena in a semicylindrical concave boundary excited by a line source located on the boundary surface are investigated in this paper. The field observed at an arbitrary position in the boundary can be represented in terms of contributions from the direct ray, “legitimate rays” with a maximum finite number of reflections, and an integral type interference wave accounting for “illegitimate rays” with too many reflections. The validity of the field representation is confirmed numerically by comparison with the reference solution obtained rigorously from the whispering gallery mode series and continuous spectrum representation. The integral type interference wave plays an important role for the observation point located in the interference region. When the observation point is outside the interference region, the field can asymptotically be expressed by geometrical ray(s) only. The width of the interference region and the number of geometrical rays for an arbitrary observation point are also discussed.
In this paper, several types of fiber dye lasers have been studied. One is the active core type fabricated by fiber drawing from a molten polymer-dye mixture, and another is the active clad type with a dye-doped clad on a plastic core. Under pulsed N2 laser pumping, these active fibers generate intense emission of the ASE mode with the spectrum width of 3_??_5 nm. Relatively efficient operations at various wavelengths are obtained. These results indicate that these fiber dye lasers are useful as a light source for the fiber sensing and other applications.