Localized epitaxial growth of tetragonal and hexagonal WSi2 on (111)Si

Both epitaxial tetragonal and hexagonal WSi2 (t-WSi2 and h-WSi2) were grown locally on (111)Si. The best epitaxy was obtained in 600–1100 °C two-step annealed samples. The orientation relationships between t-WSi2 and Si are [110]WSi2∥[111]Si and (004)WSi2∥(2̄02), whereas those between h-WSi2 and Si are [0001]WSi2∥[111]Si and (202̄0)WSi2∥(202̄)Si. Interfacial dislocations, 80 Å in spacing, were identified to be of edge type with (1/6)〈112〉 Burgers vectors. Two step annealings were found to be effective in improving the epitaxy and relieving the island formation of WSi2 on Si. Significant intermixing of W and Si atoms during the preannealing is proposed to account for the effects.