Formation of Thin Oxide Films by Metal-Organic Chemical Vapour Deposition

Abstract

A summary is given of the metal-organic vapour deposition, performed during the last eight years at the University of Twente (The Netherlands), of thin alumina, silica, and titania films at atmospheric and at low pressure on stainless steels. Alumina films were produced from aluminium-tri-sec-butoxide (ATSB) and aluminium-tri-iso-propoxide (ATI), silica films from di-acetoxy-di-t-butoxy-silane (DADBS), and titania films from titanium-tetra-iso-propoxide (TTIP). These investigations can be separated into a number of projects: 1) mechanistic aspects of the decomposition chemistry of the precursors, 2) kinetics of the deposition processes, 3) chemical properties, and 4) mechanical properties of the thin oxide films.In this paper a summary is presented with respect to the deposition of thin alumina, silica and titania films 245 Brought to you by | Purdue University Libraries Authenticated Download Date | 6/3/15 12:30 AM Vol. 15, No. 4, 1996 Formation of Thin Oxide Films by Metal-Organic Chemical performed at the University of Twente during the last eight years (March 1987-March 1995. In addition to the decomposition mechanisms of several precursors (metal alkoxides, the kinetics of the deposition process and the chemical and mechanical properties of the deposited oxide films are also presented. EXPERIMENTAL PROCEDURES Specimen preparationDepositions were performed on AISI 304 (18% Cr, 8% Ni, 0.08% C, 1% Si, 2% Mn, 71% Fe) and Incoloy 800H (20% Cr, 32% Ni, 0.08% C, 0.5% Si, 0.7% Mn, 0.4% Al, 47% Fe). The samples were cut from an electropolished sheet or were ground on SiC paper with a final size of 4000 grit, followed by a polishing treatment with alumina (3 μπι) and subsequently ultrasonically cleaned for 30 minutes in RBS soap, hexane and ethanol. Finally, the samples were immersed in Struer's etching fluid (5% solution of 3 Μ nitric acid in ethanol) for 15 minutes, washed with pure ethanol and dried in air at room temperature.

Mechanical and barrier properties of MOCVD processed alumina coatings on Ti6Al4V titanium alloy

“…It is recalled that under such conditions, the composition, microstructure and crystallinity of the alumina films strongly depend on the deposition temperature. These grown in the range 350°C-415°C are amorphous and partially hydroxylated AlO 1 + x (OH) 1 …”

“…Metalorganic Chemical Vapor Deposition (MOCVD) of alumina has been reported many times in the literature. However, only a few works explicitly deal with the deposition of amorphous alumina films [1]. Significant work has been provided by the authors in the recent years in this field.…”

“…Significant work has been provided by the authors in the recent years in this field. Especially, the relation between the operating conditions of Metalorganic Chemical Vapor Deposition (MOCVD) and the characteristics of the obtained amorphous Al 2 O 3 coatings, including the modeling of the process considering appropriate chemical kinetic schemes [1][2][3][4][5][6] was discussed. The rationale of these investigations is based on two pillars: the first concerns the moderate deposition temperature which is compatible with the thermal loads the substrate can tolerate without modification of its microstructure and, consequently of its properties and performance.…”

CVD of Al2O3 Thin Films Using Aluminum Tri‐isopropoxide

“…The necessary water for the hydrolysis is made available by the further pyrolytic decomposition of the precursor. Haanappel et al [24] assumed that ATI decomposes, to a minor extent, by a free radical or an a-hydride elimination mechanism and suggested bhydride elimination as the most plausible mechanism. Their investigations show that ATI undergoes the elimination of isopropanol and propene by b-hydride elimination at 200 C, followed by a second pyrolysis at 280 C forming AlO(OH) molecules which absorb onto the growing film interface.…”

CVD‐Fabricated Aluminum Oxide Coatings from Aluminum tri‐iso‐propoxide: Correlation Between Processing Conditions and Composition

“…Compositional uncertainties are frequently reported for the films prepared at the lowest temperatures. More fundamental approaches were tentatively carried out with films grown in hot-wall reactors, by Morssinkhof (temperature range 523-723 K) [33][34][35][36] and by Yoshikawa et al. (temperature range 573-723 K).…”