STUDY ON STRESS OF THE FILMS APPLIED TO FeRAM

ABSTRACT

For the integrated ferroelectric memory device, stress of every film in integrated ferroelectric capacitor is an important factor that can influence the properties of ferroelectric capacitor. Stresses of every film in integrated Pt/PZT/Pt capacitor are studied in this work. The PZT film is fabricated by sol-gel method. Al₂O₃ layer prepared by RF sputtering serves as the Hydrogen barrier interlayer, which presents a little tensile stress. SiO₂ layer prepared by RF sputtering is applied to FeRAM as dielectric layer, which generates some compressive stress. The sputtering SiO₂ dielectric layer can compensate the influence to ferroelectric capacitors due to tensile stresses from other layers.

Keywords:

• Ferroelectric
• stress
• sputtering
• Hydrogen barrier interlayer
• PZT

ACKNOWLEDGMENTS

This work is supported by National Natural Science Foundation of China (90407023), and “863” Program of China (2004AA404240).

The authors would like to thank Mr. Zhang Xun, Mr. Yang Yi, Mr. Zhu Yiping and Mr. Zhong Zhiyong for their help and discussion in this experiment.