Step distribution in the Si 111/surface and its effect on microstructure of MBE-grown single- and multi-layered films

Using atomic force microscopy, we investigate step distribution and band structure composed of steps in the Si 111. surface, which is used as a substrate in the formation of metallic multi-layered films by MBE. There are two kinds of bands: a. the band where steps uniformly exist band A. and b. the band where wide terraces grow with the bunched steps at both sides band B.. The width of band B follows normal distribution, in which the average value is 0.6 mm, while the width of band A distributes up to a few mm and does not follow any well-known regular distribution function. In the formation mechanism of the band structure, the terrace growth is dominant. The band structure is passed from the Si substrate to MBE-grown single- and multi-layered films. Grain size and step density of the films are influenced by the density of the Si surface step and the grain size is larger in the region where Si step density is low. Thus, it is important to control step distribution in substrates to control the microstructure of MBE-grown films. q1998 Elsevier Science B.V. All rights reserved.