LOW-VOLTAGE PERFORMANCE OF PB(ZR,TI)O-3 CAPACITORS THROUGH DONOR DOPING

We report low voltage (1.5-3 V) performance of ferroelectric Pb(Zr,Ti) O-3 based capacitors. La substitution up to 10% was performed to syste matically lower the coercive and saturation voltages of epitaxial ferr oelectric capacitors grown on Si using a (Ti0.9Al0.1)N/Pt conducting b arrier composite. Ferroelectric capacitors substituted with 10% La sho w significantly lower coercive voltage compared to capacitors with 0% and 3% La. This is attributed to a systematic decrease in the tetragon ality (i.e., c/a ratio) of the ferroelectric phase. Furthermore, the s amples doped with 10% La showed dramatically better retention and puls e width dependent polarization compared to the capacitors with 0% and 3% La. These capacitors show promise as storage elements in low power high density memory architectures. (C) 1997 American Institute of Phys ics. [S0003-6951(47)02750-2].