CONTROL OF REACTION-MECHANISM OF PHOTOCHEMICAL VAPOR-DEPOSITION OF ALUMINUM FILM BY TIMING OF SOURCE INTRODUCTION

In photochemical vapor deposition of aluminum film using dimethyaluminum hydride (DMAH) under illumination of a deuterium lamp, a photolytic reaction became dominant when silicon wafer was exposed to DMAH at room temperature prior to substrate heating to 230-degrees-C for deposition, while only a pyrolytic reaction took place when DMAH was introduced after the substrate was heated to 230-degrees-C. A scanning tunneling microscope study showed formation of Al islands in high density with the DMAH exposure, while well-isolated islands were revealed without the initial exposure. Activation sites created by chemisorption may be responsible for the observed effects.