Mixed-phase Ni-Al as barrier layer against perovskite oxides to react with Cu for ferroelectric memory with Cu metallization

JOURNAL OF ALLOYS AND COMPOUNDS

卷:666

Article

Chen, J. H.¹  Dai, X. H.¹  Li, C. R.^2,3  Cui, Y. L.¹  Zhao, Q. X.¹  Guo, J. X.¹  Li, X. H.⁴  Zhang, X. Y.⁴  Wang, Y. L.¹  Ma, L. X.⁵  Liu, B. T.¹ 

[1] Hebei Univ, Coll Phys Sci & Technol, Hebei Key Lab Opt Elect Informat & Mat, Baoding 071002, Peoples R China

[2] Zhejiang Sci Tech Univ, Dept Phys, Ctr Optoelect Mat, Hangzhou 310018, Zhejiang, Peoples R China

[3] Zhejiang Sci Tech Univ, ATMMT Minist Educ, Key Lab, Hangzhou 310018, Zhejiang, Peoples R China

[4] Yanshan Univ, State Key Lab Metastable Mat Sci & Technol, Qinhuangdao 066004, Hebei, Peoples R China

[5] Blinn Coll, Dept Phys, Bryan, TX 77805 USA

关键词: Ferroelectric capacitor;    Cu metallization;    Barrier layer;    Ni-Al;    Failure mechanism;    Interfaces;   

DOI  :  10.1016/j.jallcom.2016.01.100

来源: Elsevier

【 摘 要 】

The microstructures, interfaces, and physics properties of the devices with multifunctional barrier materials are investigated to achieve integration of perovskite oxide films with Cu film on Si for the application in nonvolatile Si-based ferroelectric random access memories (FeRAMs) with the on-chip copper metallization of advanced microelectronic devices. La(0.5)Sr(0.)5CoO(3)/Pb(Zr0.4Ti0.6)O-3/La0.5Sr0.5CoO3 (LSCO/PZT/LSCO) capacitors have been successfully fabricated on the Cu/Ni-Al/SiO2/Si stack structure for Cu interconnects using an amorphous Ni-Al (a-Ni-Al) film as the barrier layer for the Cu/SiO2 interface and a mixed-phase nanocrystalline NieAl (n-Ni-Al)/a-Ni-Al ((n+a)-Ni-Al) bi-layer-like film as the oxygen diffusion barrier layer for the LSCO/Cu interface, respectively. The perfect structure compatibility and clear interfaces between thin films are achieved. Excellent physical properties of the capacitor, such as high remnant polarization (similar to 26 mu C/cm(2)), good reliability and dielectricity, powerfully confirm that Ni-Al film can be used as the barrier layer between Cu and SiO2 or LSCO. The barrier properties of the (n+a)-Ni-Al can be understood as two aspects: n-Ni-Al component can level up the roughness of Cu/barrier/SiO2/Si surface and relax stresses in the multilayer stack heterostructure, and a-Ni-Al can inhibit oxygen penetration. Compared to the (n+a)-Ni-Al, only n-Ni-Al film without a-Ni-Al layer couldn't prevent Cu oxidation due to oxygen penetration leading to the failure of devices, whose failure mechanism can be ascribed to the reactions between Cu and complex oxides. The results fully illustrate the viability of the lead-based ferroelectric capacitors grown on Cu/Barrier/SiO2/Si stack structure with NieAl barrier for the future ferroelectric capacitor based devices with Cu metallization. (C) 2016 Elsevier B.V. All rights reserved.

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