Microstructure and mechanical properties of Zr–Si–N films prepared by rf-reactive sputtering

Abstract

ZrN and ZrSiN films were prepared in an rf sputtering apparatus that has a pair of targets facing each other (referred to as the facing target—type rf sputtering). Films were deposited on silicon wafers without bias application or substrate heating in order to examine only the effect of silicon addition to the transition metal nitride films. The contents of zirconium, nitrogen, and silicon of the films were determined with an electron probe microanalyzer. The transmission electron microscopy studies were carried out in addition to x-ray diffraction. For the high resolution transmission electron microscopy observation, the field emission type transmission electron microscope was used, which provides a point-to-point resolution of 0.1 nm. The samples were observed both parallel and perpendicular to the film surface, which were plane and cross sectional views, respectively. In order to investigate the relationship between the mechanical properties and microstructure of films, the hardness was measured by a nanoindentation system at room temperature. The load was selected to keep the impression depth below 60 nm (not more than 5% of film thickness) so that the influence from the substrate can be neglected. The hardness of the films increases with small Si additions reaching the maximum value of 35 GPa at around 3 at. % Si. The tendency to grow columnar grains was strongest around this composition, while grains became equiaxial above 5 at. % of Si. The films containing 12.8% Si, which showed the lowest hardness of 18 GPa, consist of nanocrystal grains. The presence of ZrN nanocrystals embedded in Si3N4 was not observed in the present study. The hardening mechanism due to the addition of small amounts of Si in ZrN can not be determined at this time. The grain size and residual stress can make minor contributions to the hardening. A possibility of solid solution hardening due to atomistic strain, such as nitrogen atoms at interstitial sites or other point defects is postulated and should be examined further.

Effect of germanium addition on the properties of reactively sputtered ZrN films

“…Independently of their Ge content, amorphous-like Zr-Ge -N films exhibit a constant hardness of 17.5 T 0.5 GPa. This value is close to that reported for amorphous Zr -Si -N films [12,14,15], indicating that in amorphous-like Zr -X -N films (X = Si or Ge), the hardness seems to be independent of the Si or Ge concentration. On the other hand, crystallised Zr -Ge -N films with Ge concentration lower than about 1 at.% exhibit a hardness higher than 30 GPa.…”

Influence of Target Material on the Microstructure and Properties of Ti–Si–N Coatings Prepared by r.f.-Reactive Sputtering

“…The similar relationship was also observed in the previous report of Zr-Si-N films. 11,12) On the other hand, the Ti-Si-N films containing more than 15%Si shows hardness lower than that of TiN films despite the films consisting of nanocrystallites less than 10 nm. Ti-Si-N films containing about 20%Si indicated low hardness of $20 GPa, which is similar to the results reported by other researchers.…”

“…A deposition of adhesion-layer of Ti-Si onto the substrate was followed by the deposition of Ti-Si-N coating by reactive sputtering. Based on the result of our previous study of TiN film preparation, the Ar gas flow rate was fixed at 10 sccm, and the flow rate of N 2 gas was brought back gradually from the highest flow rate to 2.5 sccm along the hysteresis loop of reactive sputtering 3,4,12) in order to obtain metal-like titanium nitride films. The working pressure was kept at $0:15 Pa (1.1 mTorr).…”

“…3,4) Recent studies of transition metal nitride films of wear-protective coatings have been aiming to explore multi component systems for improving hardness and/or oxidation resistance. Since Vepřek et al presented a theoretical concept for the super-hard ''nanocomposite'' films and their experimental verification on the Ti-Si-N systems prepared by plasma assisted CVD (PACVD), 5,6) many researchers have extensively studied mechanical properties and/or oxidation resistance of Ti-Si-N coatings [7][8][9][10] and other systems such as ZrSi-N, 11,12) Cr-Ni-N, 13) Ti-Mo-N 13) deposited by PVD. Among the previous studies on Ti-Si-N coatings, some films fabricated by PVD showed super hardness.…”

Mechanical and Structural Studies of Ternary Mo–Zr–N Layers Deposited on Substrate by PVD

“…The layers Zr-N won a lot of attention recently in various sectors, such as in microelectronics, as barriers of broadcasting in integrated circuits [17,18], thanks to their weak electric resistivity [19] in comparison with Ti-N and for applications of the hard covers thanks to a big corrosion resistance [20,21], a big hardness [22,23], a weak coefficient of friction [24], a good adhesion with the support, and a very important electric and thermal conductivity [25,26].…”