Fatigue characteristics of PZT thin films prepared by low thermal budget process

We investigated a low thermal budget process for ferroelectric film formation of Pb(ZrTi)O₃ (PZT) thin films. A low temperature film growth and post RTA treatment revealed that the crystallization of PZT thin films strongly depends on RTA time, temperature, and Pb excess percentage. We achieved a pure perovskite structure and excellent hysteresis loop characteristics for an RTA time of 10 seconds at 600°C. Process optimized Pd/PZT/Pt capacitors demonstrated a coercive field of 45 kV/cm and a remanent polarization of 26 μC/cm² after 700°C RTA for 60 seconds. With an increase of RTA temperature, PZT capacitors showed an improvement in fatigue properties. The capacitor RTA treated at 700°C exhibited almost no decrease of Pr value even for switching cycles higher than 1×10⁹ cycles. Using an XPS analysis, we clearly identified that the cause of the fatigue is the Pb-rich layer formation at the PZT film surface. This phenomenon is strongly dependent on the crystallization process and Pb excess percentage