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Materials for Thin Films

RHP puts research efforts in further developing sputtering target materials together with partners as well as own developments.

One example ist the process of thermal diffusion coating used for applying thin metal coatings of e.g. Cr onto diamond particles. This technology is cheap, fast and easy to apply. It also forms a strong interface between the diamond particle and the metal coating layer.

For multi-phase sputtering targets a strong focus is on fine-grained and homogeneously distributed components. The rapid hot pressing technologies allow for example to consolidate a dens Ti-Al Target material with a very small amount of fine distributed intermetallic phases. Typically Ti-Al targets are used as starting material for hard TiAlN films.

A fine distributed microstructure could be achieved by using the powder metallurgical route. However when Ti and Al powder is mixed and hot pressed with a conventional resistance heated hot pressing technique, thick intermetallic layers and pores can be found in the microstructure (c). Our study proved that this disadvantage can be solved by using a rapid hot pressing technique such as SPS/FAST or direct hot pressing.

By selecting a proper Ti-powder and using short hot pressing cycles dens and fine distributed Ti-Al Materials with a limited amount of intermetallic phases could be consolidated (b). The picture shows three different Ti-Al samples. Sample (a) is consolidated with a rapid hot pressing technique but with a finer Ti-powder. Sample (b) is also consolidated with a rapid hot pressing technique but with larger Ti-particles. Sample (c) is as (b) consolidated with larger Ti-particles but with a much longer hot pressing cycle (typical for conventional resistance heated hot pressing). The three samples indicate that both particle size and cycle time are essential parameters in the forming of a dens Ti-Al material with a limited amount of intermetallic phases.

a) Fine Ti powder and short hot pressing cycle
b) Larger Ti-particles and short hot pressing cycle
c) Larger Ti-particles but longer hot pressing cycle