AVS 56th International Symposium & Exhibition
    Thin Film Thursday Sessions
       Session TF-ThM

Paper TF-ThM3
Spontaneous Growth of In-whiskers from In-Y Thin Films Prepared by Combinatorial Magnetron Sputtering Technique

Thursday, November 12, 2009, 8:40 am, Room B4

Session: Nanostructuring Thin Films II
Presenter: T. Takahashi, RWTH Aachen University, Germany
Authors: T. Takahashi, RWTH Aachen University, Germany
A. Abdulkadhim, RWTH Aachen University, Germany
D. Music, RWTH Aachen University, Germany
J.M. Schneider, RWTH Aachen University, Germany
Correspondent: Click to Email
In-Y binary thin films with a composition gradient were prepared using a combinatorial magnetron sputtering technique. In-whiskers grow spontaneously from the film surface at room temperature upon exposure to air. Whisker morphology and population vary with the In to Y ratio. An appreciable amount of In-whiskers is formed at film compositions close to In-25 at.%Y. The In-whisker thickness ranges from a few hundreds nanometers to a few micrometers.

In order to identify the whisker growth mechanism, temporal changes of the film surface upon air exposure were captured using scanning electron microscopy. X-ray micro diffraction was employed for studying the structural evolution during the In-whisker growth in air. The results show that the In-whiskers grow not from the tip but from the root. The whisker growth rate was as high as 150 nm/s. The growth of In-whiskers is found to be related to the incorporation of oxygen into the film during air exposure. Correspondingly, the In concentration within the film decreases as In-whiskers grow. The mechanism of the spontaneous In-whisker growth presented here can be understood based on the stress-induced extrusion of In-whiskers due to the selective room temperature oxidation of Y in sputtered In-Y thin films.