Title :
Effect of interconnect layer on Pb(Zr,Ti)O3 thin film capacitor degradation
Author :
Kobayashi, Sota ; Amanuma, Kazushi ; Hada, Hiromitsu
Author_Institution :
Silicon Syst. Res. Labs., NEC Corp., Kanagawa, Japan
Abstract :
Ferroelectric properties of a Pb(Zr,Ti)O/sub 3/ (PZT) thin film capacitor with a conventional Al/TiN/Ti interconnect layer are seriously degraded by annealing at around 400/spl deg/C. The degradation is observed even if a contact hole on the top electrode is not formed. This indicates that the cause of the degradation is not the diffusion of the interconnect material into the PZT film, and this is confirmed by secondary ion mass spectrometry. We suggest that it is the thermal strain of the interconnect layer which imposes tensile stress on the PZT film during the annealing that degrades the ferroelectric properties of the PZT capacitor.
Keywords :
annealing; dielectric hysteresis; dielectric polarisation; ferroelectric capacitors; ferroelectric storage; ferroelectric thin films; lead compounds; secondary ion mass spectroscopy; thermal stresses; thin film capacitors; 400 C; Al-TiN-Ti-SiO/sub 2/-Ir-IrO/sub 2/-PZT-Pt-TiO/sub 2/-SiO/sub 2/-Si; Al-TiN-Ti-SiO2-Ir-IrO2-PbZrO3TiO3-Pt-TiO2-SiO2-Si; Al/TiN/Ti interconnect layer; PZT thin film capacitor degradation; Si; annealing; ferroelectric properties; hysteresis loop; interconnect layer effect; nonvolatile ferroelectric RAM; polarization properties; secondary ion mass spectrometry; tensile stress; thermal strain; Annealing; Capacitors; Electrodes; Ferroelectric films; Ferroelectric materials; Mass spectroscopy; Thermal degradation; Thermal stresses; Tin; Transistors;
Journal_Title :
Electron Device Letters, IEEE
