Texture and microstructure of Cr2O3 and (Cr,Al)2O3 thin films deposited by reactive inductively coupled plasma magnetron sputtering

Cr2O3 and (Cr,Al)2O3 films were grown using reactive dc and inductively coupled plasma magnetron sputtering at substrate temperatures of 300-450 °C. For pure chromia, α-Cr2O3 films with fiber texture were grown; the out-of-plane texture could be controlled from < 0001> to < 101̅4>. The former texture was obtained as a consequence of competitive growth with no applied bias or inductively coupled plasma, while the latter was obtained at moderate bias (− 50 V), probably due to recrystallization driven by ion-bombardment-induced strain. By reactive codeposition of Cr and Al, a corundum-structured metastable solid solution α-(Cr,Al)2O3 with Cr/Al ratios of 2-10 was grown with a dense, fine-grained morphology. Hardness and reduced elastic modulus values were in the ranges 24-27 GPa and 190-230 GPa, respectively.