Interfacial reactions of rf-sputtered TiNi thin films on (100) silicon with a SiN diffusion barrier
Journal
Philosophical Magazine
Journal Volume
84
Journal Issue
12
Pages
1209-1218
Date Issued
2004
Author(s)
Abstract
Silicon nitride (SiN) with a 50 nm thickness on Si(100) as a thermal barrier was obtained by plasma-enhanced chemical vapour deposition (PECVD). TiNi thin films were rf sputtered on a SiN/Si substrate and then annealed at 400–700°C for 30 min. Their interfacial reactions were studied using transmission electron microscopy, X-ray diffraction and Auger electron spectroscopy analyses. Experimental results show that the thickness of reaction layer in TiNi/SiN/Si specimens is clearly reduced, compared with that in TiNi/Si specimens under the same annealing conditions. The significant effect of the SiN layer as a diffusion barrier in TiNi/SiN/Si can be recognized. N and Si atoms diffuse from the SiN layer to react with TiNi films at 500°C and 600°C respectively. The TiN1 − x phase is formed in specimens annealed at 500°C, and mixed Ti2Ni3Si and Ti4Ni2O compounds are found at 600°C. In the specimen annealed at 700°C, the reaction layer has sublayers in the sequence TiNi/Ti4Ni2O/Ti2Ni3Si/TiN1 − x /SiN/Si. The SiN thermal barrier obtained by PECVD caused quite different diffusion species to cross the interfaces between TiNi/SiN/Si and TiNi/Si specimens during the annealing.
Type
journal article