Phase transformations in Ta-Si system induced by compression plasma flow

¹ B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 70 Nezavisimosti ave., Minsk 220072, Belarus
² A.V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15, P. Brovki str., Minsk 220072, Belarus
³ Belarusian State University of Informatics and Radioelectronics, 6 Brouki str., Minsk 220013, Belarus
⁴ Belarusian State University, 4 Nezavisimosti ave., Minsk 220030, Belarus

^a e-mail: a.sari@dragon.bas-net.by

Received: 23 July 2013
Revised: 1 November 2013
Accepted: 4 December 2013
Published online: 6 January 2014

Abstract

In this study, the effect of a dense compression nitrogen plasma flow on a microstructure and the elemental and phase compositions of a “tantalum layer-silicon substrate” system is investigated. Predeposited tantalum thin films (∼2 μm thick) on Si(1 1 1) and Si(1 0 0) substrates were exposed to a single plasma pulse or to a series of pulses. The power density absorbed by the target, plasma pulse duration and discharge current were 1.2 GW/m², 100 μs and 80 kA, respectively. The temperature field distribution and its time evolution were approximately simulated. SEM and EDX analyses revealed the presence of tantalumrich domains consisting of nano-sized particles and spherical multilevel structures. X-ray diffraction analysis showed the formation of crystalline hexagonal tantalum-rich silicides and tantalum nitride. A mechanism explaining the structural changes and phase transformation of the Ta/Si system is proposed.