Study On?-phase Seeds Promoting The Deposition Of ?-Al₂O₃ Films And Its Properties By Reactive Sputtering At Low Temperature

?-Al₂O₃ with corundum structure has broad application prospects in high speed tool coating,microelectronics field and anti-penetration layer for its excellent comprehensive properties such as high temperature hardness,good chemical stability,high electrical insulation and good tritium penetration resistance.It is easy to form various metastable phases when depositing alumina at low temperature,which limits the application of alumina thin films.The growth of?-Al₂O₃ at low temperature could be effectively promoted by pre-planting?-phase seeds on substrate surface in reactive magnetron sputtering method,thus reducing the deposition temperature of single phase?-Al₂O₃ film.In this paper,the?-Al₂O₃ and?-Cr₂O₃seeds were employed on substrate surface to realize low-temperature deposition?-Al₂O₃ film and corundum structure Al-Cr-O films.The carrying out research results were list as follows.The alumina films were deposited at the substrate temperature in the range of 480-560?by radio frequent reactive sputtering Al+?-Al₂O₃ composite target.With the increase of substrate temperature,the content of the?-Al₂O₃ and amorphous phase decreased and that of?-Al₂O₃ increased in the films,and single phase?-Al₂O₃ film could be prepared at 560?.Consequently,the hardness and elastic modulus of alumina films improved and reached the maximum at 560?.The hardness and elastic modulus of the single phase?-Al₂O₃ film were24.3 GPa and 236.8 GPa,respectively.With pre-planting?-Al₂O₃ seeds on the gold foil substrate,alumina films were deposited by reactive sputtering Al target.Single phase?-Al₂O₃ film could be deposited at 500?with higher distribution density of the seeds.On the substrate surface,alumina molecules directly diffused to?-Al₂O₃ seeds for growth which would inhibit the nucleation of?-Al₂O₃.Therefore,the required temperature for the deposition of single phase?-Al₂O₃ film could be reduced.The?-Cr₂O₃ seeds were employed continuously and uniformly on the substrate surface by reactive co-sputtering Al target and Cr target.Then,corundum structure Al-Cr-O films were deposited at low temperature.The mutual diffusion of Al³⁺and Cr³⁺in the films could be promoted by increasing the substrate temperature which led to form?-(Al,Cr)₂O₃ solid solution.The Al-Cr-O films were composed of?-Cr₂O₃,?-Al₂O₃ and?-(Al,Cr)₂O₃ deposited at 450?and 500?.Single phase?-(Al,Cr)₂O₃ film was prepared at 550?when Cr content of the film was 33.3 at%,and its hardness and elastic modulus were 24.8 GPa and 221.2 GPa,respectively.