ABUKAWA Tadashi Tohoku University, Research Institute for Scientific Measurements, Research Asso, 科学計測研究所, 助手 (20241581)
TAKAKUWA Yuji Tohoku University, Research Institute for Scientific Measurements, Associate Pro, 科学計測研究所, 助教授 (20154768)
|Budget Amount *help
¥2,500,000 (Direct Cost : ¥2,500,000)
Fiscal Year 1996 : ¥2,500,000 (Direct Cost : ¥2,500,000)
We have developed an apparatus suitable for analyzing structures and chemical compositions of local surfaces. This apparatus is composed of a micro-electron beam and a retarding-field two-dimensional display-type electron energy analyzer (RDA analyzer) and called mu-GBMEED ; abbreviation for Grazing-incidence Backscattering Medium Energy Electron Diffraction. The method of GBMEED has been invented by the head investigator in which a monochromatic electron beam of an energy of 1 to 3 keV is incident on a specimen surface at a grazing angle and elastically scattered electrons along backward direction are analyzed by the RDA analyzer. This dives us a so-called mu-GBMEED pattern. By analyzing this pattern, structural and compositional information about local surface of an order of -0.1 mum can be obtained. The apparatus has been realized by combining a commercial mu-electron beam gun and a home-made RDA analyzer on a specially designed ultrahigh vacuum chamber. Signals from the RDA analyze
r are recorded with a CCD-camera system which mu-GBMEED patterns with a wide-solid angle can be efficiently stored in a computer memory. The apparatus is also combined with a UHV-STM system, so that atomic-scale STM images on the same specimen surface can be measured and used as a guide for thr analysis by mu-GBMEED.
As a test of the apparatus, we have investigated a Si (001) surface in order to determine the backling angle of the buckled Si-dimers wich are known to be present. The buckling angle is reported to be about 19^ﾟ but is not so certain. A single domain Si (001) 2x1 surface was investigated with mu-electron beam at 1 to 2 KeV and mu-GBMEED patterns were recorded. With the aid of presently developed single-scattering method for GBMEED,a forward-scattering diffraction feature was found. However, the quality of the pattern was not good enough to finally determine the buckling angle. We are in the stage of improving the quality of GBMEED patterns by several means.