Improved interfacial and electrical properties of atomic layer deposition HfO2 films on Ge with La2O3 passivation

• Published in: Applied surface science 2013-01, Vol.264, p.783-786
• Main Authors: Li, Xue-Fei, Liu, Xiao-Jie, Cao, Yan-Qiang, Li, Ai-Dong, Li, Hui, Wu, Di
• Format: Article
• Language: English
• Subjects: HfO2; Interfacial passivation layer; La2O3; MOS capacitor
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.10.127

► La2O3 IPLs were deposited on Ge substrates at 250°C by ALD using La[N(SiMe3)2]3 and H2O as the precursors. ► CET of 1.35nm and leakage current of 8.3×10−4A/cm2 at Vg=1V are observed for the HfO2/La2O3 gate stack on Ge substrate. ► The improvement in the interfacial and electrical properties is related to the formation of a stable LaGeOx interfacial layer. We report the characteristics of HfO2 films deposited on Ge substrates with and without La2O3 passivation at 250°C by atomic layer deposition (ALD) using La[N(SiMe3)2]3 and Hf[N(CH3)(C2H5)]4 as the precursors. The HfO2 is observed to form defective HfGeOx at its interface during 500°C postdeposition annealing. The insertion of an ultrathin La2O3 interfacial passivation layer effectively prevents the Ge outdiffusion and improves interfacial and electrical properties. Capacitance equivalent thickness (CET) of 1.35nm with leakage current density JA of 8.3×10−4A/cm2 at Vg=1V is achieved for the HfO2/La2O3 gate stacks on Ge substrates.