AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP2
Mechanical Properties and Residual Stresses in AlN Films Prepared by Ion Beam Assisted Deposition

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: Y. Watanabe, National Defense Academy, Japan
Authors: Y. Watanabe, National Defense Academy, Japan
N. Kitazawa, National Defense Academy, Japan
Y. Nakamura, National Defense Academy, Japan
C. Li, Osaka University, Japan
T. Sekino, Osaka University, Japan
K. Niihara, Osaka University, Japan
Correspondent: Click to Email
Aluminum nitride (AlN) thin films were prepared on silicon single crystal substrates by ion-beam assisted deposition method, and the influence of the nitrogen ion beam energy on mechanical properties and residual stresses was studied by changing the nitrogen ion beam energy from 0.1 to 1.5 keV. Mechanical properties were examined by a nano-indentation method and residual stresses were evaluated by film curvature measured by an optical cantilever system. The films show elastic behaviors during loading and unloading processes, but the residual depth after the unloading process increases with increasing the ion beam energy, resulting in decreasing in the returned energy ratio. All the films are found to be in compressive stress state and the values of the stress decrease with increasing the ion beam energy. Decreasing tendency is also observed in the relationship between the ion beam energy and film hardness. So as to study the effect of thermal treatment on relaxation of residual stresses, the films were annealed in nitrogen atmosphere at 723 K, and it is found that the films prepared with the high energy ion beam are relaxed more easily than those prepared with the low energy ion beam. These results suggest that rearrangement of AlN occurs readily in the films prepared with the high energy ion beam. It is proposed that the mechanical properties and residual stresses are closely related with each other and they can be controlled by the ion beam energy.