Improvements in electrical properties of hydrogen-treated SrBi2Ta2O9 capacitors with chemical vapor deposited Pt top electrode

Abstract

The ferroelectric property and leakage current of metalorganic chemical vapor deposition (MOCVD)-Pt/SrBi2Ta2O9 (SBT)/Pt and dc-sputtered Pt/SBT/Pt capacitors are evaluated with the microstructures of Pt top electrodes before and after hydrogen forming gas anneal. The SBT films with MOCVD-Pt top electrodes of large grain size and dense structure show a surprising decrease of leakage current density and still exhibit ferroelectric properties after hydrogen forming. On the other hand, SBT films with dc-sputtered Pt top electrodes of small grain size show an increase of leakage current density and then polarization switching properties cannot be measured due to fairly high leakage current. The microstructures of Pt top electrodes play an important role in improving the ferroelectric and leakage current characteristics after forming gas anneal. MOCVD-Pt top electrodes can prevent the complete loss of ferroelectricity and improve the leakage current properties during forming gas treatment.

EFFECT OF GRAIN SIZE ON THE FERROELECTRIC PROPERTIES OF Bi3.25La0.75Ti3O12 Thin Films

“…The grain size dependence of the ferroelectric and dielectric properties in AB0 3 type materials is known for many years. Several models for grain size effects in ferroelectric thin films have been proposed by different authors, which take into account effects such as the electrodes/film interfacial layer [4], stresses [5], defects [6], and domain structure transition [7].…”