Chemical Composition of AlN Thin Films Deposited at 523−723 K Using Dimethylethylamine Alane and Ammonia

• Published in: Chemistry of materials 1998-03, Vol.10 (3), p.777-783
• Main Authors: Kidder, J. N, Yun, H. K, Rogers, J. W, Pearsall, T. P
• Format: Article
• Language: English
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Composition and phase identification; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm970556u

We have investigated a process for depositing AlN thin films at temperatures less than 800 K via surface reactions between specially chosen precursors. An Al precursor, dimethylethylamine alane (DMEAA, (CH3)2C2H5N:AlH3) was used with ammonia (NH3), and the reactants were delivered to the growth surface in separate steps using an atomic layer growth (ALG) process to promote film formation through a sequence of surface reactions. AlN thin films were deposited on Si(100), Si(111), Al2O3(00.1), and Al2O3(01.2) substrates at 523−723 K using a range of process flow conditions. Auger and X-ray photoelectron spectroscopy were employed to characterize the chemical composition of the films. These measurements detected carbon and oxygen contamination at the surface and smaller concentrations in the bulk. In the high-resolution X-ray photoelectron spectroscopy C(1s) data, binding energies for C−H and C−N species were identified but no C−Al species were present. In the N(1s) data, N−O species were not detected, but chemically bonded H was present in the films as NH3 - x (x = 0−2) species. The composition varied with process conditions, and the hydrogen content decreased in AlN films processed above 600 K.