Growth of γ-alumina thin films by pulsed laser deposition and plasma diagnostic

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2017-07, Vol.123 (7), p.1-11, Article 464
• Main Authors: Yahiaoui, K., Abdelli-Messaci, S., Messaoud Aberkane, S., Siad, M., Kellou, A.
• Format: Article
• Language: English
• Subjects: Alumina; Aluminum oxide; Applied physics; Backscattering; Biological evolution; Characterization and Evaluation of Materials; Condensed Matter Physics; Crystallization; Diagnostic software; Diagnostic systems; Electronic devices; Hardness; Machines; Manufacturing; Materials science; Mechanical analysis; Modulus of elasticity; Nanotechnology; Optical and Electronic Materials; Optical emission spectroscopy; Oxygen; Physics; Physics and Astronomy; Plasmas (physics); Processes; Pulsed laser deposition; Spectroscopic analysis; Spectrum analysis; Stoichiometry; Structural analysis; Surfaces and Interfaces; Temperature; Thin Films; Transitional aluminas; X-ray diffraction
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-017-1074-3

The present work discusses about the synthesis of alumina thin films, which have applications in current and next-generation solid-state electronic devices due to their attractive properties. Alumina thin films were synthesized by pulsed laser deposition at different oxygen pressures and substrate temperatures. The dependence of substrate temperature, oxygen pressure, and the deposition time on the properties of the films has been observed by growing three series of alumina thin films on Si (100). The first films are synthesized using substrate temperatures ranging from room temperature to 780 °C at 0.01 mbar of O 2 . The second series was realized at a fixed substrate temperature of 760 °C and varied oxygen pressure (from 0.005 to 0.05 mbar). The third set of series was elaborated at different deposition times (from 15 to 60 min) while the oxygen pressure and the substrate temperature were fixed at 0.01 mbar and 760 °C, respectively. The films were characterized using X-ray diffractometer (XRD) for structural analysis, a scanning electron microscope for morphological analysis, a nano-indenter for mechanical analysis (hardness and Young’s modulus), and Rutherford backscattering spectroscopy for thickness and stoichiometry measurements. Using optical emission spectroscopy, plasma diagnostic was carried out both in the vacuum and in the presence of oxygen with a pressure ranging from 0.01 to 0.05 mbar. Several neutral, ionic, and molecular species were identified such as Al, Al + , and Al ++ in vacuum and in oxygen ambiance, O and AlO molecular bands in oxygen-ambient atmosphere. The spatiotemporal evolution of the most relevant species was achieved and their velocities were estimated. The highest amount of crystallized alumina in γ-phase was found in the films elaborated under 0.01 mbar of O 2 , at a substrate temperature of 780 °C, and a deposition time of 60 min.