Sticking probabilities of H2O and Al(CH3)3 during atomic layer deposition of Al2 O3 extracted from their impact on film conformality

Karsten Arts (Corresponding Author), Vincent Vandalon, Riikka L. Puurunen, Mikko Utriainen, Feng Gao, Wilhelmus M.M. Erwin Kessels, Harm C.M. Knoops (Corresponding Author)

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    11 Citations (Scopus)


    The conformality of a film grown by atomic layer deposition (ALD) is strongly affected by the reactivities of the precursor and coreactant, which can be expressed in terms of their sticking probabilities toward the surface. We show that the leading front of the thickness profile in high-aspect-ratio structures gives direct information on the sticking probabilities of the reactants under most conditions. The slope of the front has been used to determine the sticking probabilities of Al(CH3)3 and H2O during ALD of Al2O3 . The determined values are (0.5-2) × 10-3 for Al(CH3)3 and (0.8-2) × 10-4 for H2O at a set-point temperature of 275 °C, corresponding to an estimated substrate temperature of ∼220 °C. Additionally, the thickness profiles reveal soft-saturation behavior during the H2O step, most dominantly at reduced temperatures, which can limit the conformality of Al2O3 grown by ALD. This work thus provides insights regarding quantitative information on sticking probabilities and conformality during ALD, which is valuable for gaining a deeper understanding of ALD kinetics.

    Original languageEnglish
    Article number030908
    JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
    Issue number3
    Publication statusPublished - 24 Apr 2019
    MoE publication typeA1 Journal article-refereed


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