Mechanisms of Atomic Layer Deposition on Substrates with Ultrahigh Aspect Ratios

Langmuir, 24 (3), 943 -948, 2008. 10.1021/la7018617 S0743-7463(70)01861-9
Web Release Date: January 1, 2008

Mechanisms of Atomic Layer Deposition on Substrates with Ultrahigh Aspect Ratios

S. O. Kucheyev,* J. Biener, T. F. Baumann, Y. M. Wang, and A. V. Hamza

Nanoscale Synthesis and Characterization Laboratory, Lawrence Livermore National Laboratory, Livermore, California 94551

Z. Li, D. K. Lee, and R. G. Gordon

Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138

Received June 22, 2007

In Final Form: October 23, 2007

Abstract:

Atomic layer deposition (ALD) appears to be uniquely suited for coating substrates with ultrahigh aspect ratios (10³), including nanoporous solids. Here, we study the ALD of Cu and Cu₃N on the inner surfaces of low-density nanoporous silica aerogel monoliths. Results show that Cu depth profiles in nanoporous monoliths are limited not only by Knudsen diffusion of heavier precursor molecules into the pores, as currently believed, but also by other processes such as the interaction of precursor and reaction product molecules with pore walls. Similar behavior has also been observed for Fe, Ru, and Pt ALD on aerogels. On the basis of these results, we discuss design rules for ALD precursors specifically geared for coating nanoporous solids.

Download the full text: PDF | HTML