J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (10): 2305-2311.DOI: 10.1016/j.jmst.2019.05.028

• Orginal Article • Previous Articles     Next Articles

Ta-doped modified Gd2O3 film for a novel high k gate dielectric

Shuan Liab, Yanqing Wub, Guoling Lic, Hongen Yub, Kai Fuab, Yong Wuab, Jie Zhangb, Wenhuai Tiana*(), Xingguo Lib*()   

  1. a Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China
    b Beijing National Laboratory of Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
    c College of Materials Science and Engineering, Qingdao University, Qingdao 266071, China
  • Received:2019-03-08 Revised:2019-04-16 Accepted:2019-04-30 Online:2019-10-05 Published:2019-08-28

Abstract:

Gadolinium oxide (Gd2O3) film has potential as a candidate gate dielectric to replace HfO2. In this work, we provide a simple method by trace Ta ($\widetilde{1}$%) doping to significantly improve the dielectric properties of Gd2O3 film. And effects of annealing temperatures of Ta-doped Gd2O3 (GTO) films are investigated in detail. Results show that GTO film annealed at 500 °C exhibits excellent performance as a novel gate dielectric material for integrated circuit, showing a small surface roughness of 0.199 nm, a large band gap of 5.45 eV, a high dielectric constant (k) of 21.2 and a low leakage current density (Jg) of 2.10 × 10-3 A/cm2. All properties of GTO films are superior to pure Gd2O3 films and these GTO films meet the requirements for next-generation gate dielectrics. In addition, impedance spectrum is first used to analyze the equivalent circuit of GTO based metal-oxide-semiconductor (MOS) capacitors, which represents a new insight to understand observed electrical behaviors.

Key words: Rare earth oxides, High k film, Magnetron sputtering, Annealing temperature, Gate dielectrics