Abstract
This article reports on stress, structure and thermal stability of Al-Si-Cu-N films prepared by DC reactive magnetron sputtering. The films were deposited under the following conditions: discharge current Id=1A, substrate bias Us=-100V, substrate ion current density is=0.6 and 0.9mA/cm2, substrate temperature Ts=300°C and 500°C, substrate-to-target distance ds-t=60mm, partial pressure of nitrogen pN2 ranging from 0.06 to 0.14Pa and constant total pressure pT=pAr+pN2=0.5Pa. It was found that [1] the macrostress σ increases with increasing pN2 and [2] the films sputtered at very low values of pN2 (i) are polycrystalline films consisting of Al and small amounts of Al2Cu, (ii) are in tension and (iii) have a mat appearance due to a rough surface. According to the changes in structure during annealing up to 700°C, the Al-Si-Cu-N films can be divided into two groups: (a) metastable films which are characterized by a crystalline structure and (b) stable films which exhibit an X-ray amorphous structure. The metastable films change their structure upon thermal annealing. On the contrary, the stable films remain amorphous even after annealing at Ta=700°C for 30min. The stable films contain a high (approx. 8at%) amount of copper and exhibit the lowest thermal expansion coefficient αc≈4.2×10-6K-1 compared to the metastable films with αc≈10-12×10-6K-1. The experiments described in this paper show that the thermal expansion coefficient of the films strongly depends on their structure.
Original language | English |
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Pages (from-to) | 21-28 |
Number of pages | 8 |
Journal | User Modeling and User-Adapted Interaction |
Volume | 72 |
Issue number | 1 |
DOIs | |
Publication status | Published - 12 Sep 2003 |
Keywords
- Al-Si-Cu-N films
- Macrostress σ
- Magnetron sputtering
- Structure
- Thermal stability
ASJC Scopus subject areas
- Instrumentation
- Condensed Matter Physics
- Surfaces, Coatings and Films