Rapid Vapor Deposition of Highly Conformal Silica Nanolaminates
Dennis Hausmann,
Jill Becker,
Shenglong Wang,
Roy G. Gordon*
Highly uniform and conformal coatings
can be made by the alternating exposures of a surface to vapors of two
reactants, in a process commonly called atomic layer deposition (ALD).
The application of ALD has, however, been limited because of slow
deposition rates, with a theoretical maximum of one monolayer per
cycle. We show that alternating exposure of a surface to vapors of
trimethylaluminum and tris(tert-butoxy)silanol deposits
highly conformal layers of amorphous silicon dioxide and aluminum oxide
nanolaminates at rates of 12 nanometers (more than 32 monolayers) per
cycle. This process allows for the uniform lining or filling of long, narrow holes. We propose that these ALD layers grow by a previously unknown catalytic mechanism that also operates during the rapid ALD of
many other metal silicates. This process should allow improved production of many devices, such as trench insulation between transistors in microelectronics, planar waveguides,
microelectromechanical structures, multilayer optical filters, and
protective layers against diffusion, oxidation, or corrosion.
Department of Chemistry and Chemical Biology, Harvard University,
12 Oxford Street, Cambridge, MA 02138, USA.
*
To whom correspondence should be addressed. E-mail:
gordon{at}chemistry.harvard.edu
