Integration of epitaxial Pb(Zr0.52Ti0.48)O3 films on GaN/AlGaN/GaN/Si(111) substrates using rutile TiO2 buffer layers

• Published in: Thin solid films Vol. 591; pp. 66 - 71
• Main Authors: Elibol, K., Nguyen, M.D., Hueting, R.J.E., Gravesteijn, D.J., Koster, G., Rijnders, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30-09-2015
• Subjects: Buffer layers; Ferroelectric materials; Ferroelectric properties; Ferroelectricity; Gallium nitride; Gallium nitrides; Heterostructures; Lead zirconate titanate; Lead zirconate titanates; Pulsed laser deposition; Rutile; Rutile titanium dioxide; Structural properties; Thin film optimization; Titanium dioxide; X-rays; Thin film optimization; Rutile titanium dioxide; Pulsed laser deposition; Ferroelectric properties; Gallium nitride; Heterostructures; Structural properties; Lead zirconate titanate
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2015.07.069

The integration of ferroelectric layers on gallium nitride (GaN) offers a great potential for various applications. Lead zirconate titanate (PZT), in particular Pb(Zr0.52Ti0.48)O3, is an interesting candidate. For that a suitable buffer layer should be grown on GaN in order to prevent the reaction between PZT and GaN, and to obtain PZT with a preferred orientation and phase. Here, we study pulsed laser deposited (100) rutile titanium oxide (R-TiO2) as a potential buffer layer candidate for ferroelectric PZT. For this purpose, the growth, morphology and the surface chemical composition of R-TiO2 films were analyzed by reflection high-energy electron diffraction, atomic force microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We find optimally (100) oriented R-TiO2 growth on GaN (0002) using a 675°C growth temperature and 2Pa O2 deposition pressure as process conditions. More importantly, the R-TiO2 buffer layer grown on GaN/Si substrates prevents the unwanted formation of the PZT pyrochlore phase. Finally, the remnant polarization and coercive voltage of the PZT film on TiO2/GaN/Si with an interdigitated-electrode structure were found to be 25.6μC/cm2 and 8.1V, respectively.
•Epitaxial rutile TiO2 films were grown on GaN layer buffered Si substrate using pulsed laser deposition.•The rutile-TiO2 layer suppresses the formation of the pyrochlore phase in the epitaxial PZT film grown on GaN/Si.•An epitaxial PZT film on GaN/Si substrate with rutile TiO2 buffer layer exhibits good ferroelectric properties.