Imec paper
Imec publishes on epitaxial BaTiO3 for silicon photonics, deposited by Solmates PLD

Barium titanate (BaTiO3 or BTO) is a perovskite material that shows interesting ferroelectric and electro-optical behavior that strongly depend on the crystallinity of the thin film. Pulsed laser deposition (PLD) is a very promising growth technique for such functional oxide systems due to the precise stoichiometry control and the ability to grow epitaxial layers in relative short deposition time.

In this research, an epitaxial BTO layer is grown by PLD onto a Si(001) substrate thanks to a thin pseudomorphic SrTiO3 buffer layer grown by MBE. The various investigated PLD parameters show strong impact on the BTO polarization orientation. Hence, adjusting the growth conditions allows control of the polarization orientation, which is crucial for both electronic and optical applications. In addition, lattice parameter changes of BTO layers are investigated using x-ray diffraction and cross-sectional transmission electron microscopy, which evidenced a correlation between mismatch relaxation and oxygen growth pressure. Finally, with the analysis of BTO C–V curves, the polarization direction transition is demonstrated electrically.

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