摘要
The vacancy ordering structures of epitaxial TbSi 2-x , ErSi 2-x , YSi 2-x , and DySi 2-x thin films on (001)Si and (111)Si have been investigated by electron diffraction analysis. From a combination of studying planview and cross-sectional transmission electron microscope samples, the 3-dimensional structures of vacancy ordering were determined. The vacancy ordering superstructure of unit cell (a√3 a√3 2c) was found in epitaxial TbSi 2-x , ErSi 2-x and YSi 2-x thin films on (001)Si samples. However, the vacancy ordering superstructure of unit cell (a√3 a√3 c) was found in epitaxial TbSi 2-x and DySi 2-x thin films on (111)Si samples. The variation in strains induced in these films is suggested to result in the change of the vacancy ordering structure.