Process induced poling and plasma induced damage of thin film PZT

- The effect of Ar ion milling on properties of epitaxial PZT films are investigated.
- Direct ion bombardments worsen PZT permittivity and reliability.
- The plasma charging may influence the poling of virgin PZT capacitors.
- The process induced positively charged defects may initiate the dielectric breakdown.

This paper treats processing sequence induced changes on PZT. Two kinds of metal-PZT-metal capacitors are compared. The top surface and sidewall of PZT in one kind of capacitor is directly bombarded by energetic particles during ion milling process, whereas PZT in the other kind of capacitor is not. The polarity of plasma charging may depend on the ion milling parameters and influence the self-poling of virgin PZT capacitors. Direct ion bombardment induces a significant decrease of PZT permittivity. The PZT reliability (both RVS and TDDB) at positive voltage worsens because of bombardments of energetic particles; whereas the PZT reliability at negative voltage is not influenced. It indicates that the process induced positively charged defects present in the upper part of the capacitor structure initiate the dielectric breakdown.

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