COLUMNAR EPITAXY OF PTSI ON SI(111)

Columnar grains of PtSi surrounded by high quality epitaxial silicon are obtained by ultrahigh vacuum codeposition of Si and Pt in an 8:1 ratio on Si(111) substrates heated to 610-810°C. The areal density of columns varies from 120 to 3.8 μm-2, and layers with thicknesses from 100 nm to 1 μm have been demonstrated. This result is similar to that found previously for CoSi2 (a nearly lattice-matched cubic-fluorite crystal) on Si(111), in spite of the orthorhombic structure of PtSi. The PtSi grains are also epitaxial and have one of three variants of the relation defined by PtSi(010)//Si(111), with PtSi[001]//Si〈110〉.