US Patent 7695994 Material sidewall deposition method

A method of forming a layer of material on a sidewall of a via with good thickness control. The method involves forming a layer of material with a conventional deposition process. The material formed on a field region surrounding the via is removed with a sputter etch process. Another layer of material is deposited thereon, wherein the sputter etch-deposition cycle is repeated as necessary to achieve a desired sidewall thickness. With this method, the thickness of the material deposited on the sidewall is linearly dependent on the number of process cycles, thus providing good thickness control. The method may be used to form a resistance variable material, e.g., a phase-change material, on a via sidewall for use in a memory element.