Surface-science investigations of the metallization of semiconductors by photochemical deposition and related techniques

Abstract

Surface-sensitive techniques have been employed to investigate chemical reactions involved in the photochemical deposition of metals onto semiconductors. The specific systems examined are Fe deposition [from Fe(CO)5] and W deposition (from WF6) onto Si(100). Pyrolytic, photolytic (Hg-arc lamp), and spontaneous surface chemical processes, which are all expected to contribute to the overall reactions, have been examined individually. The data indicate that both vapor precursors exhibit a nonspecific physical interaction with Si, although chemisorption may occur when metal is present on the surface. Molecular processes involved in the pyrolytic and photolytic decomposition of the vapor precursors are identified. The advantages offered by photochemical techniques over alternative pyrolytic and electron-stimulated reactions are discussed.