Cm. Foster et al., IN-SITU GROWTH OF PB(ZR0.5TI0.5)O-3 RUO2 HETEROSTRUCTURES ON SI(001) USING LOW-TEMPERATURE METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION/, Integrated ferroelectrics, 14(1-4), 1997, pp. 23-31
Pb(Zr0.5Ti0.5)O-3/RuO2 thin film heterostructures were successfully gr
own on SiO2/Si(001) substrates using metal-organic chemical vapor depo
sition with a maximum processing temperature of 525 degrees C. To form
the heterostructures, (110)-textured RuO2 electrode layers were first
deposited on SiO2/Si(001) substrates at temperatures as low as 350 de
grees C at a typical grow rate of similar to 40 Angstrom/min.. The res
istivity of the RuO2 films was 30-40 mu Omega-cm. Plan-view transmissi
on electron microscopy (TEM) and atomic force microscopy (AFM) showed
that typical RuO2 films had a grain size of 800-1000 Angstrom with sur
face roughness of 3-25 nm, respectively. Perovskite phase Pb(Zr0.5Ti0.
5)O-3 (PZT) was then deposited at 525 degrees C. The as-deposited film
s exhibited a dense, randomly-oriented crystal structure with a grain
size of similar to 800-1000 Angstrom. Using capacitors defined with Ag
top electrodes, the film showed a remanent polarization of 21.5 mu C/
cm(2) and a coercive field of 39.0 kV/cm. The capacitors showed little
fatigue up to similar to 10(10) cycles. The as-deposited films exhibi
ted high resistivity (10(12)-10(13) Omega-cm at 100 kV/cm). The curren
t versus voltage characteristics show that the films have typical diel
ectric breakdown strengths of similar to 60 V/mu m with a sub-breakdow
n leakage current density of 5 x 10(-5) A/cm(2).