A paradigm shift in thin film growth by magnetron sputtering: towards metal-ion-controlled process

Viktiga resultat som projektet gav

Projektet syftade till att utveckla nya processer för högkvalitativa beläggningar vid lägre substrattemperaturer. Detta innebär en paradigmskifte i tunnfilmstillväxt genom att ersätta traditionellt använt gasjonbestrålning med metalljoner. Vi visade att massan av infallande metalljoner spelar en avgörande roll för kvaliteten på beläggningar som avsatts utan extern uppvärmning. Vi erhöll hårda och täta TiAlWN-beläggningar vid substrattemperaturer inte högre än 130 ° C (jämfört med vanligtvis 400-500 ° C). Processenergiförbrukningen sänktes med 65%.

Långsiktiga effekter som förväntas

Coatings deposited with Cr+ irradiation (TiAlCrN) exhibited porous nanostructure, high oxygen content and poor mechanical properties. In contrast, TiAlWN films were fully-dense even with the lowest W concentration, showed no evidence of hexagonal AlN precipitation, and exhibited mechanical properties typical of TiAlN grown at 500 °C. Thus, our new film growth concept allows to substitute the thermally-driven adatom mobility with that supplied by effective low-energy recoil creation by heavy metal ion irradiation. The process energy consumption is lowered by 65%.

Upplägg och genomförande

Three series of TiAlMeN films (Me = Cr, Mo, or W) were grown by a combination of DC and HiPIMS sputtering with no external heating resulting in that the substrate temperature did not exceed 130 C during growth (typically 400-500 °C is used in industry). The effect of metal ion mass was studied (varied from 52.0 amu for Cr to 183.8 amu for W). Results showed very conclusively that irradiation with lower mass ions does not produce high quality TiAlCrN coatings irrespective of Cr dose. In contrast, as little as 5 at.% of W supplied in the form of W+ enables deposition of dense and hard TiAlWN layers.