(6), (9) To deposit crystalline alumina phases, substrate temperatures higher than 500[degrees]C are generally required.
(6.) Li, Q, Yu, YH, Bhatia, CS, Marks, LD, Lee, SC, Chung, YW, "Low-Temperature Magnetron Sputter-Deposition, Hardness and Electrical Resistivity of Amorphous and Crystalline Alumina Thin Films." J.
(12.) Schneider, JM, Sproul, WD, Voevodin, AA, Matthews, A, "Crystalline Alumina Deposited at Low Temperatures by Ionized Magnetron Sputtering." J.
(20) In the former case, thickening of the amorphous film proceeds at both the metal/Film and film/environment interfaces, through co-operative transport of O2- and Al3+ ions across the pre-existing film: for crystalline alumina
development at sufficiently elevated temperatures, this usually proceeds below the amorphous film at sites where molecular oxygen can react with the substrate.