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 semi conducting electronic properties, with promising application in thermoelect ric devices. This paper reports the structural and morphological properties of HMS prepared by a reactive deposition process on Si(001) under UHV cond itions. X-ray diffraction shows, for all samples grown at substrate tempera tures ranging from 400 to 750 degreesC, the growth of KR;IS only. Scanning electron microscopy and Rutherford backscattering spectrometry show a trans ition from him growth to island growth with increasing substrate temperatur e. 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 o n the basis of anisotropic growth rates for differently oriented grains of HMS. (C) 2001 Elsevier Science B.V. All rights reserved.