Pulse width dependent activation voltage measurements of ferroelectric (Pb,La)(Zr,Ti)O3 thin film capacitors for nonvolatile memories

We report pulse width and pulse voltage dependent pulse current responses of 10% La doped and undoped Pb(Zr0.2Ti0.8)O3 (PZT) thin film capacitors. With increasing pulse voltage, polarization increases above coercive voltage, and then saturates at higher voltages. With longer pulse width, polarizations increase and coercive voltages decrease. Activation voltages are calculated from the switching current response. La doping effects are discussed in terms of activation voltages for ferroelectric domain reversal. 10% La doped PZT (PLZT) has less coercive and activation voltages and, as a result, pulse polarizations of PLZT are less dependent on pulse width and voltage compared to PZT.