Mechanical Properties, Stress Relaxation and High Temperature Thermal Stability of Nanolayered Mo-Si-N/SiC Thin Films.

Microstructure, thermal stability, nanoindentation mechanical properties and stress relaxation of nanolayered Mo-Si-N/SiC thin films have been studied. Multilayers of Mo-Si-N (MoSi22N2.5) and SiC were deposited by magnetron sputtering from planar MoSi2 and SiC targets on to the single crystal siliconwafers. The relative amount of both components was varied (12.5-50 vol% of SiC) while keeping bilayer thickness constant (12 nm), or the bilayer thickness was varied (6-24 nm) with constant Mo-Si-N to SiC ratio (25 vol% of SiC) Mechanical properties were measured by nanoindentation on as-deposited films and films annealed in vacuum at 500* C and 900* C. Microstructure and thermal stability were examined by cross-sectional transmission electron microscopy (XTEM), glancing angle X-ray diffraction (GAXRD9) and nuclear resonance broadening (NRB). Stress relaxation induced by thermal annealing and heavy ion irradiation (400 keV Ar2+) was determined by measuring optically the change in curvature of coated silicon stress beams. The interface between Mo-Si-N and SiC was shown to be stable at least up to 41 h anneal at 1075* C in vacuum. The potential of Mo-Si-n barrier layer against intermixing between nanolayered MoSi2 and SiC has been demonstrated. The residual stress in the multilayered structure turns out to be a composition of stresses in both constituents and follows the rule-of-mixture. significant stress relaxation in all films was shown to occurr during annealing for even a short period of 15 min at 500* C. Consequently, by optimizing the volume fraction of the constituents zero residual stress on a silicon substrate is possible after annealing. Ion bombardment reduces residual stress on as-deposited films probably through an irradiation induced densification of amorphous material.

TORRI P.;  HIRVONEN Juha-Pekka;  KUNG H.;  LU Y.C.;  NASTASI M.;  GIBSON Peter Neil; 

1998-10-13

JRC17177

https://publications.jrc.ec.europa.eu/repository/handle/JRC17177,