Back to Search
Start Over
Stress and surface morphology of TiNiCu thin films: effect of annealing temperature
- Source :
-
Surface & Coatings Technology . Aug2005, Vol. 198 Issue 1-3, p389-394. 6p. - Publication Year :
- 2005
-
Abstract
- Abstract: TiNi-based films sputtered at room temperature are amorphous; thus, postsputtering annealing is a must because shape memory effect only occurs in their crystalline form. It is suggested that the lowest possible annealing temperature be used in a bid to conserve thermal processing budgets, and to minimize thermal stresses and possible interfacial reactions between film and its substrate. In this paper, Ti49.5Ni47.5Cu3 (at.%) films with a thickness of 3.5 μm were deposited on Si substrate by cosputtering of TiNi and Cu targets at room temperature, then annealed at different temperatures from 430 to 650 °C. Phase transformation behaviors, crystalline structure, residual stress and stress evolution of the films were systematically studied. At the gas pressure of 0.8 mTorr, the residual stress in the as-deposited films was 260 MPa, compressive. A minimum annealing temperature (450 °C) was necessary for film crystallization; thus, large thermal stress could be released significantly due to martensitic transformation. With increase of annealing temperature, crystallite and martensite plate sizes in the film increased; thus, both recovery stress and stress-increase rate increased, while the transformation temperatures shifted to higher values. The surface roughness increased drastically with increase of annealing temperature in correlation to martensitic transformation. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 02578972
- Volume :
- 198
- Issue :
- 1-3
- Database :
- Academic Search Index
- Journal :
- Surface & Coatings Technology
- Publication Type :
- Academic Journal
- Accession number :
- 18003068
- Full Text :
- https://doi.org/10.1016/j.surfcoat.2004.10.107