Characteristics of SrBi2Ta2O9 ferroelectric films on GaAs with a TiO2 buffer layer

Mainly [115]-oriented SrBi2Ta2O9 (SBT) films were prepared on GaAs(100) substrates with TiO2 buffer layers. Both the SBT films and the TiO2 buffer layers were deposited by pulsed laser deposition (PLD) using a KrF excimer laser. The depth profile of the constituent elements observed by Auger electron spectrometry (AES) shows no remarkable diffusion at both the interfaces between SBT and TiO2 and between TiO2 and the GaAs substrate. The electrical characteristics of the Pt/SBT/TiO2/GaAs(100) structures show a ferroelectric hysteresis loop with a small remanent polarization (similar to0.5 muC/cm(2)). that can transfer complex monolayer structures from ceramic targets onto substrates. In the present study, a buffer layer of TiO2 was deposited on GaAs using PLD to fabricate a SBT/GaAs heterostructure with good interface properties. We expected that the use of thin TiO2 films as buffer layers would preserve the GaAs surface at deposition temperatures as high as 700 degreesC and within an oxygen-rich environment. The depth profile of the constituent elements for the SBT/TiO2/GaAs structure is shown. The crystallographic structure and electrical properties of the Pt/SBT/TiO2/GaAs structure are investigated.