This work described the electrical characteristics of a kind of amorphous Gd2O3-doped HfO2 insulator for high-k metal-oxidesemiconductor (MOS) capacitors.Compared with pure HfO2,the doped HfO2 with an optimum concentration of Gd2O3 as MOS gate dielectric exhibited a lower leakage current,thinner effective oxide thickness and less fixed oxide charges density.The result indicated that Gd2O3 doping power of 60 W exhibited the best electrical characteristics,maximum capacitance,lowest leakage current of 9.35079×10-7 A/cm2,and minimum fixed oxide charge density of 3.59×109 cm-2.The lower electronegativity and larger atomic radium of Gd contributed to the improvement in the leakage current for Gd2O3-doped HfO2 films.The electrical characteristics of Gd2O3-doped HfO2 thin film illustrated that it is a promising gate dielectric layer for future high-k gate dielectric applications.