Abstract: Zirconium diboride (ZrB₂) has excellent electrical properties,thermal stability and mechanical properties,which makes it widely applied in the field of microelectronic products and high-temperature ceramics.The composition and microstructure can be regulated by element doping.ZrB₂ thin films with different Al content were prepared on Si (100) substrate by magnetron co-sputtering.The chemical composition,microstructure and electrical properties of Zr-Al-B thin films were analyzed by X-ray photoelectron spectroscopy,scanning electron microscopy,atomic force microscopy,X-ray diffraction and four point probe.The results show that aluminum doping will affect the composition and microstructure of zirconium boride films and further affect the electrical properties.The films prepared at different Al sputtering power have flat surface,compact structure and polycrystalline structure.With the increasing of Al/Zr atomic content ratio,the film structure changes from pure ZrB₂ to ZrB₂ and Al₂O₃ composite phase.Moreover,with the increase of Al/Zr atomic ratio,the resistivity firstly decreases and then increases,and the minimum resistivity is 0.027Ω·cm,indicating that appropriate amount Al doping can improve the electrical properties of ZrB₂ films.