Etching Effects on Ferroelectric Capacitors with Multilayered Electrodes

Dry etching of PbZr X Ti1- X O3 (PZT) thin film capacitors with RuO X /Pt multilayered electrodes was studied to examine the etching effects. PZT films were deposited on RuO X /Pt/Ti/SiO2/Si substrates by sol–gel process and Pt films were prepared by DC magnetron sputtering. PZT and Pt thin films were etched with Cl2/C2F6/Ar gas combination in an inductively coupled plasma (ICP) by varying the etching parameters such as coil RF power, dc-bias voltage to wafer susceptor, and gas pressure. Etching effects were investigated in terms of etch rate, etch selectivity, etch profiles, and electrical properties of etched capacitors. Quantitative analysis of the etching damage was obtained by calculating the shift of the coercive field and the switchable polarization in hysteresis loops. Finally, the etching damage mechanism was discussed and the optimization of etching processes for the fabrication of PZT capacitors was attempted to minimize the etching damage to ferroelectric capacitors.