CVD of Al₂O₃ Thin Films Using Aluminum Tri‐isopropoxide

Abstract

A stagnation point cold-wall reactor was used for the CVD of corundum alumina (a-Al 2 O 3 ) on metallic substrates. Depositions were carried out under low pressure using the thermally induced pyrolytic oxidation of aluminum tri-isopropoxide (ATI). The effects of the substrate temperature (300±1080 C) and the total pressure (50±250 mbar) on the growth rate and morphology of the deposits were investigated. An excess of oxygen facilitates the formation of dense alumina films. Precursor depletion was prevented using high gas velocity, low ATI concentration, and a high temperature gradient. X-ray diffraction (XRD) analysis provided evidence of corundum alumina deposition at substrate temperatures above 1000 C.

Amorphous Alumina Barrier Coatings on Glass: MOCVD Process and Hydrothermal Aging

“…[ 7,[11][12][13] CVD is one of the most attractive techniques for the time effi cient deposition of such coatings on complexin-shape geometries with conformal coverage, i.e., uniform thickness along the surface. Composition, stoichiometry, crystallinity, and microstructure of the material can be adjusted by fi ne tuning of the MOCVD experimental parameters such as reactor design, precursor selection, reactive atmosphere, deposition temperature, and pressure.…”

“…The MOCVD of alumina from vaporized aluminum tri-isopropoxide (ATI) is very well documented. [ 7,8,[11][12][13][14][15][16] ATI yields amorphous and stoichiometric alumina coatings with a smooth and dense microstructure at 5 Torr in the temperature range 420 to 650 °C. [ 7,8,14,15 ] Higher process temperatures lead to the deposition of nanocrystallized γ -Al 2 O 3 [ 15 ] or to the homogeneous decomposition of ATI, which generates a different microstructure.…”

“…[ 7,8,14,15 ] Higher process temperatures lead to the deposition of nanocrystallized γ -Al 2 O 3 [ 15 ] or to the homogeneous decomposition of ATI, which generates a different microstructure. [ 11 ] The ATI molecule is well described in the literature.…”

“…This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 15772 [ 9 ] radio frequency magnetron sputtering, [ 2 ] atomic layer deposition, [ 10 ] sol-gel, [ 5 ] and metalorganic chemical vapor deposition (MOCVD). [ 7,[11][12][13] CVD is one of the most attractive techniques for the time effi cient deposition of such coatings on complexin-shape geometries with conformal coverage, i.e., uniform thickness along the surface. Composition, stoichiometry, crystallinity, and microstructure of the material can be adjusted by fi ne tuning of the MOCVD experimental parameters such as reactor design, precursor selection, reactive atmosphere, deposition temperature, and pressure.…”

“…[ 7,8,14,15 ] Higher process temperatures lead to the deposition of nanocrystallized γ -Al 2 O 3 [ 15 ] or to the homogeneous decomposition of ATI, which generates a different microstructure. [ 11 ] The ATI molecule is well described in the literature.[ 17 ] It is sensitive to water vapor and thus it is subjected to ageing upon exposure to ambient atmosphere, which results in its partial or total hydrolysis in nonvolatile compounds, Al(O i Pr) 3− n (OH) n ( n = 1, 2) and Al(OH) 3 , respectively. [ 12,17 ] The precursor is usually melted, maintained in supercooled state, and vaporized with a bubbler.…”