Surface mechanisms in aluminum chemical vapor deposition

Abstract

Triisobutylaluminum (TIBA) can be used to selectively grow patterned aluminum films in chemical vapor deposition. This is possible because film nucleation occurs much more rapidly on a metal or semiconductor surface than on an oxide surface. In this study we examine the adsorption and decomposition of TIBA on a silicon oxide surface. Two of the three isobutyl groups in the TIBA are removed easily upon adsorption on a silicon oxide surface, but the third isobutyl group will not decompose thermally. Ultraviolet laser irradiation has previously been shown to be effective at aiding film growth by decomposing adsorbed organometallics and creating adsorbed metal particles that act as nucleation sites for thermal growth. We show here that x rays are also effective at decomposing the isobutyl groups through some surface mediated process such as generation of hot electrons, but only when the surface is heated. Chemical changes in the surface are linked to this process.