Abstract
Both epitaxial tetragonal and hexagonal WSi 2 (t-WSi 2 and h-WSi 2 ) were grown locally on (111)Si. The best epitaxy was obtained in 600-1100°C two-step annealed samples. The orientation relationships between t-WSi 2 and Si are [110]WSi 2 ∥ [111]Si and (004)WSi 2 ∥(2̄02), whereas those between h-WSi 2 and Si are [0001]WSi 2 ∥[111]Si and (202̄0)WSi 2 ∥(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 WSi 2 on Si. Significant intermixing of W and Si atoms during the preannealing is proposed to account for the effects.