Study On ?-?Al,Cr?₂O₃ Thin Films And Its Properties Deposited By Reactive Sputtering At Low Temperature

Corundum-type?-?Al,Cr?₂O₃ has high lattice energy and various excellent properites,which are similar to that of?-Al₂O₃.?-?Al,Cr?₂O₃ has a wide application prospect in the fields of wear resistance,electrical insulation,diffusion barrier and tritium permeation barrier coatings because of its high hardness at room temperature and high temperature,excellent chemical stability,high electrical insulation and low tritium permeability.The properities of the solid solution?-?Al,Cr?₂O₃ are closely related to the relative content of?-Al₂O₃ and?-Cr₂O₃.With the increasing of the content of?-Al₂O₃,the thermal stability,dielectric and insulation properties of the material are improved accordingly.In this paper,the Al/Cr/?-Al₂O₃ targets were used for reactive sputtering deposition at low temperature.In order to prepare Al-rich?-?Al,Cr?₂O₃ films at low temperature,this research used?-Al₂O₃ to replace?-Cr₂O₃ as seed crystal.The results are as follows.The substrate temperature had a significant effect on the microstructure of the films deposited by redio frequency ractive sputtering Al₈₀Cr₁₅??-Al₂O₃?₅ target.When the substrate temperature is 500?,the phase composition of the films was?-Al₂O₃,?-Cr₂O₃ and?-Al₂O₃.With the increasing of the substrate temperature,?-Al₂O₃ transformed into?-Al₂O₃ in the films.The corundum-type?-?Al,Cr?₂O₃ films could be obtained at 600?.The Al_xCr_95-x??-Al₂O₃?₅?x=80,70,60?sputtering targets with different Cr content were designed and sintered to study the effect of substrate temperature on the phase structure of Al-Cr-O thin films with different Cr content.The results showed that the corundum-type?-?Al,Cr?₂O₃ films could be deposited at lower substrate temperature by sputtering the target with higher Cr content.Both Cr and?-Al₂O₃ in the target could provide the epitaxial growth of?phase and inhibit the nucleation of metastable alumina,which reduced the forming temperature of?phase films.The Al-rich single phase?-?Al,Cr?₂O₃ films could be prepared by sputtering Al₇₀Cr₂₅??-Al₂O₃?₅ target at a substrate temperature of 550?.The hardness and elastic modulus of the films were 30.2±1.7 GPa and 244.3±3.2 GPa,respectively.Using the Si₃N₄ceramic ball as grinding materia,the friction coefficient of the films was 0.41 and the width of wear scar was only 100?m.The permittivity and resistivity of the films were 14.8 and1.83×10⁷?·cm,respectively.The substrate temperature had a significant effect on the mechanical and electrical properties of the films deposited by ractive sputtering Al₇₀Cr₂₅??-Al₂O₃?₅ target.When the substrate temperature was lower than 550?,the hardness and elastic modulus of the films increased obviously with the increasing of the substrate temperature.When the substrate temperature was higher than 550?,the effect of substrate temperature on the hardness and elastic modulus of the film tended to be stable.With the increasing of the substrate temperature from 500?to 600?,the relative permittivity of the films decreased and the resistivity of the films increased obviously.The resistivity of the films deposited at 600?could reach2.30×10⁷?·cm.