Growth of epitaxial semiconductor films in presence of reactive metal

摘要

A method is disclosed for forming an epitaxial layer of a semiconductor material over a metal structure disposed upon a surface of a semiconductor substrate, the metal being characterized by a negative Gibbs free energy for the formation of a compound of the metal and the semiconductor material. The method comprises the steps of: a) placing the substrate in a reactor vessel having a base pressure in the ultra high vacuum range, b) bringing the substrate to an elevated temperature, and c) flowing, over said substrate, a halogen-free precursor gas of molecules comprising the semiconductor material. Typically, the metal structure characterized by feature dimensions of less than 2.0 microns. Preferably, the metal is tungsten, the semiconductor material is silicon and the gas comprises a silane of the form Si_nH_(2n+2), where n is a positive integer.