| abstract |
A method and apparatus for forming semiconductive semiconductor-metal alloy layers is described. A germanium precursor and a metal precursor are provided to a chamber, and an epitaxial layer of germanium-metal alloy, optionally including silicon, is formed on the substrate. The metal precursor is typically a metal halide, which may be provided by evaporating a liquid metal halide, subliming a solid metal halide, or by contacting a pure metal with a halogen gas. A group IV halide deposition control agent is used to provide selective deposition on semiconductive regions of the substrate relative to dielectric regions. The semiconductive semiconductor-metal alloy layers may be doped, for example with boron, phosphorus, and/or arsenic. The precursors may be provided through a showerhead or through a side entry point, and an exhaust system coupled to the chamber may be separately heated to manage condensation of exhaust components. |