Abstract
Al 2 O 3 films with precise thicknesses and high conformality were deposited using sequential surface chemical reactions. To achieve this controlled deposition, a binary reaction for Al 2 O 3 chemical vapor deposition (2A1(CH 3 ) 3 + 3H 2 O → Al 2 O 3 + 6CH 4 ) was separated into two half-reactions: (A) AlOH* + Al(CH 3 ) 3 → Al-O-Al(CH 3 )* 2 + CH 4 , (B) AlCH* 3 * + H 2 O → AlOH* + CH 4 , where the asterisks designate the surface species. Trimethylaluminum (Al(CH 3 ) 3 ) (TMA) and H 2 O reactants were employed alternately in an ABAB . . . binary reaction sequence to deposit Al 2 O 3 films on single-crystal Si(100) and porous alumina membranes with pore diameters of ∼ 220 Å. Ellipsometric measurements obtained a growth rate of 1.1 Å/AB cycle on the Si(100) substrate at the optimal reaction conditions. The Al 2 O 3 films had an index of refraction of n = 1.65 that is consistent with a film density of ρ 3.50 g/cm 3 . Atomic force microscope images revealed that the Al 2 O 3 films were exceptionally flat with a surface roughness of only ± 3 Å (rms) after the deposition of ∼ 270 Å using 250 AB reaction cycles. Al 2 O 3 films were also deposited inside the pores of Anodisc alumina membranes. Gas flux measurements for H 2 and N 2 were consistent with a progressive pore reduction versus number of AB reaction cycles. Porosimetry measurements also showed that the original pore diameter of ∼ 220 Å was reduced to ∼ 130 Å after 120 AB reaction cycles.
Original language | English (US) |
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Pages (from-to) | 128-136 |
Number of pages | 9 |
Journal | Applied Surface Science |
Volume | 107 |
DOIs | |
State | Published - Nov 1996 |
Funding
This work was supported by the Office of Naval Research under Contract No. N00014-92-J-1353 and an exploratory research grant from Chevron Research and Engineering Company. The Atomic Force Microscope was obtained by an instrumentation grant from the National Science Foundation. We would also like to thank Professor Joseph Michl and Dr. Tom Magnara for the use of the ellipsometer.
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- General Physics and Astronomy
- Surfaces and Interfaces
- Surfaces, Coatings and Films