Preparation and properties of MnSi1.7 on Si(001)

The most rich silicon silicides of manganese, the group of higher manganese silicides (HMS), have the composition MnSix with x in the range from 1.67 to 1.75. This material group with a tetragonal crystal structure shows semiconducting electronic properties, with promising application in thermoelectric devices. This paper reports the structural and morphological properties of HMS prepared by a reactive deposition process on Si(001) under UHV conditions. X-ray diffraction shows, for all samples grown at substrate temperatures ranging from 400 to 750 degreesC, the growth of KR;IS only. Scanning electron microscopy and Rutherford backscattering spectrometry show a transition from him growth to island growth with increasing substrate temperature. A detailed analysis of the XRD spectra shows a change of the texture of HMS at the transition of the sample morphology. The results are discussed on the basis of anisotropic growth rates for differently oriented grains of HMS. (C) 2001 Elsevier Science B.V. All rights reserved.