Inhibiting\nMetal Oxide Atomic Layer Deposition: Beyond Zinc Oxide

Abstract

Atomic\nlayer deposition (ALD) of several metal oxides is selectivity inhibited\non alkanethiol self-assembled monolayers (SAMs) on Au, and the eventual\nnucleation mechanism is investigated. The inhibition ability of the\nSAM is significantly improved by the in situ H₂-plasma\npretreatment of the Au substrate prior to the gas-phase deposition\nof a long-chain alkanethiol, 1-dodecanethiol (DDT). This more rigorous\nsurface preparation inhibits even aggressive oxide ALD precursors,\nincluding trimethylaluminum and water, for at least 20 cycles. We\nstudy the effect that the ALD precursor purge times, growth temperature,\nalkanethiol chain length, alkanethiol deposition time, and plasma\ntreatment time have on Al₂O₃ ALD inhibition.\nThis is the first example of Al₂O₃ ALD inhibition\nfrom a vapor-deposited SAM. The inhibitions of Al₂O₃, ZnO, and MnO ALD processes are compared, revealing the versatility\nof this selective surface treatment. Atomic force microscopy and grazing-incidence\nX-ray fluorescence further reveal insight into the mechanism by which\nthe well-defined surface chemistry of ALD may eventually be circumvented\nto allow metal oxide nucleation and growth on SAM-modified surfaces.