Mechanical properties, stress evolution and high-temperature thermal stability of nanolayered Mo–Si–N/SiC thin films

Abstract

Formation of metastable c-AlN and its effect on the mechanical properties of AlN/(Ti,Al)N nanoscale multilayersA study of the microstructure, thermal stability, nanoindentation mechanical properties, and residual stress evolution of nanolayered Mo-Si-N/SiC thin films as a function of vacuum annealing time and temperature is reported. Multilayers of Mo-Si-N (MoSi 2.2 N 2.5 ) and SiC were deposited by magnetron sputtering from planar MoSi 2 and SiC targets onto single crystal silicon wafers. The relative amount of both components was varied ͑12.5-50 vol. % of SiC͒ while keeping the bilayer thickness constant ͑12 nm͒, or the bilayer thickness was varied ͑6-24 nm͒ with constant Mo-Si-N to SiC ratio ͑25 vol. % of SiC͒. Mechanical properties were measured by nanoindentation on as-deposited films and films annealed in vacuum at 500 and 900°C. Microstructure and thermal stability were examined by cross-sectional transmission electron microscopy, glancing angle x-ray diffraction and nuclear resonance broadening. Stress evolution induced by thermal annealing was determined by measuring optically the change in curvature of coated silicon beams. In the as-deposited state, all films exhibited an amorphous microstructure. At 900°C SiC still remained amorphous, but Mo-Si-N had developed a microstructure where nanocrystals of Mo 5 Si 3 were embedded in an amorphous matrix. The interface between Mo-Si-N and SiC was indirectly shown to be stable at least up to 41 h annealing at 1075°C in vacuum. The potential of Mo-Si-N as a barrier layer against intermixing between nanolayered MoSi 2 and SiC at 900°C has been demonstrated. Hardness, modulus and residual stress followed the volume fraction rule of mixture of both constituents of the nanolayered Mo-Si-N/SiC structure. Consequently, by optimizing the volume fraction of the constituents, zero residual stress on a silicon substrate is possible after annealing.

Oxidation of nanocrystalline Mo–Si–N and nanolayered Mo–Si–N/SiC coatings

“…After 3 h of annealing at 900°C SiC was still amorphous, but Mo-Si-N had a microstructure which consists of equaxial nanocrystals (typical grain size 3.5 nm) embedded in an amorphous matrix (Fig. 26 In Fig. This amorphous matrix has a lighter contrast in TEM-bright field images than the crystalline phase.…”

X‐ray photoelectron spectroscopy of miscible poly(methyl methacrylate)/poly(styrene‐co‐acrylonitrile) and immiscible poly(methyl methacrylate)/polyacrylonitrile polymer surfaces metallized by nickel

“…In other words, nitrogen prevented the nickel from diffusing through the substrate, or, very likely, it was the nickel nitride formed at the interface that acted as a barrier for the metal mobility. Indeed, nitride species are well known for their barrier properties in the microelectronic area,12–14 and the same kind of metal nitride is suspected to be formed during the metallization of nitrogen‐containing substrates.…”

Comparative study on mechanical properties of MoSiN multilayer films deposited on Si(100) and Ti-covered Si(100) substrates

“…In addition, they have been widely used as functional film layers, such as diffusion barriers, buffer layers, and interlayers [6,7]. Multilayer films with high residual stress, hardness, and toughness, have many advantages over single-layer films due to the repeated nucleation during the film growth at the interfaces between sub-layers [8][9][10]. Amorphous and crystalline MoSiNx coatings produced by reactive sputtering of a MoSi2 source in the presence of nitrogen plasma and MoSiN films have shown good thermal stability in several multilayered composite films [11].…”