Effect of O{sub 2} gas partial pressure on mechanical properties of Al{sub 2}O{sub 3} films deposited by inductively coupled plasma-assisted radio frequency magnetron sputtering

Journal Article · Sat Sep 15 00:00:00 EDT 2012 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4746013· OSTI ID:22102195

Fujiyama, Hirokazu; Sumomogi, Tsunetaka; Nakamura, Masayoshi ^[1]

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1. Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajirohigashi, Higashi-ku, Fukuoka 811-0295 (Japan)

The effect of O{sub 2} partial pressure on the mechanical properties of Al{sub 2}O{sub 3} films is studied. Using films prepared by inductively coupled plasma-assisted radio frequency magnetron sputtering, the deposition rate of Al{sub 2}O{sub 3} decreases rapidly when oxygen is added to the argon sputtering gas. The internal stresses in the films are compressive, with magnitude decreasing steeply from 1.6 GPa for films sputtered in pure argon gas to 0.5 GPa for films sputtered in argon gas at an O{sub 2} partial pressure of 0.89 Multiplication-Sign 10{sup -2} Pa. Stress increases gradually with increasing O{sub 2} partial pressure. Using a nanoindentation tester with a Berkovich indenter, film hardness was measured to be about 14 GPa for films sputtered in pure argon gas. Hardness decreases rapidly on the addition of O{sub 2} gas, but increases when the O{sub 2} partial pressure is increased. Adhesion, measured using a Vickers microhardness tester, increases with increasing O{sub 2} partial pressure. Electron probe microanalyzer measurements reveal that the argon content of films decreases with increasing O{sub 2} partial pressure, whereas the O to Al composition ratio increases from 1.15 for films sputtered in pure argon gas to 1.5 for films sputtered in argon gas at O{sub 2} partial pressures over 2.4 Multiplication-Sign 10{sup -2} Pa. X-ray diffraction measurements reveal that films sputtered in pure argon gas have an amorphous crystal structure, whereas {gamma}-Al{sub 2}O{sub 3} is produced for films sputtered in argon gas with added O{sub 2} gas. Atomic force microscopy observations reveal that the surface topography of sputtered Al{sub 2}O{sub 3} films changes from spherical to needlelike as O{sub 2} partial pressure is increased. Fracture cross sections of the films observed by scanning electron microscopy reveal that the film morphology exhibits no discernible features at all O{sub 2} partial pressures.

• OSTI ID: 22102195
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 30, Issue 5; Other Information: (c) 2012 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM OXIDES
ARGON
ATOMIC FORCE MICROSCOPY
CRYSTAL STRUCTURE
DEPOSITION
ELECTRON PROBES
FRACTURES
MAGNETRONS
MICROHARDNESS
MORPHOLOGY
OXYGEN
PARTIAL PRESSURE
PLASMA
RADIOWAVE RADIATION
RESIDUAL STRESSES
SCANNING ELECTRON MICROSCOPY
SPUTTERING
THIN FILMS
VICKERS HARDNESS
X-RAY DIFFRACTION