Triple‐crystal x‐ray diffraction analysis of reactive ion etched gallium arsenide

This is the published version. Copyright 1994 American Institute of PhysicsThe effect of BCl3 reactive ion etching on the structural perfection of GaAs has been studied with diffuse x‐ray scattering measurementsconducted by high‐resolution triple‐crystal x‐ray diffraction. While using a symmetric 004 diffraction geometry revealed no discernible differences between etched and unetched samples, using the more surface‐sensitive and highly asymmetric 113 reflection revealed that the reactive ion etched samples etched displayed less diffusely scattered intensity than unetched samples, indicating a higher level of structural perfection. Increasing the reaction ion etch bias voltage was found to result in decreased diffuse scattering initially, until an apparent threshold voltage was reached, after which no further structural improvement was observed. Furthermore, we have shown that this reduction in process‐induced surfacestructural damage is not due merely to the removal of residual chemical‐mechanical polishing damage

SURFACE MORPHOLOGY OF MECHANICALLY AND CHEMICALLY POLISHED SEMICONDUCTOR WAFERS

Un diffractomètre 4 cercles, couplé à un détecteur bidimensionnel, est utilisé pour mesurer les tiges de Bragg tronquées provenant d'une surface cristalline plane. On montre qu'en jouant sur le degré de planéité de la surface, on peut obtenir des renseignements intéressants sur les processus fondamentaux de la diffusion de rayons X par la surface. Ainsi, il est possible de caractériser par une méthode non destructive les surfaces de semiconducteurs qui sont préparées pour une utilisation industrielle.In the, x-ray measurement of crystal truncation rod (CTR) scattering from a flat crystal surface, the conventional symetric reflection geometry with the use of a 4-circle diffractometer is shown to be still effective. Some advantages of using an imaging plate for the observation of x-ray CTR scattering are also presented. Several fundamental aspects of x-ray CTR scattering are demonstrated using several Si wafer surfaces with different degree of flatness. It is possible to characterize, by non-destructive methods, semiconductor surfaces which are treated for industrial use

Long-lasting phosphorescence in Ce-doped oxides

Although oxide crystals doped with Ce3+ are not useful in laser operation, they have advantage in the areas such as scintillators and passive optical sources. Scintillator materials require high light-yield and fast fluorescence decay time. However, when the crystalline quality is degraded by defects created during the crystal growth process, afterglow from the crystals is observable persistently. Such phosphorescence is undesirable for scintillators, but useful in passive optical sources. The phosphorescence observed in Ca2Al2SiO7 doped with Ce3+ ions has been investigated in detail and a model is proposed to explain the mechanism responsible