An atomic layer deposition method includes providing a semiconductor substrate within a deposition chamber. A first metal halide-comprising precursor gas is flowed to the substrate within the chamber effective to form a first monolayer on the substrate. The first monolayer comprises metal and halogen of the metal halide. While flowing the first metal halide-comprising precursor gas to the substrate, H2 is flowed to the substrate within the chamber. A second precursor gas is flowed to the first monolayer effective to react with the first monolayer and form a second monolayer on the substrate. The second monolayer comprises the metal. At least some of the flowing of the first metal halide-comprising precursor gas, at least some of the flowing of the H2, and at least some of the flowing of the second precursor gas are repeated effective to form a layer of material comprising the metal on the substrate.