TY - JOUR
T1 - Toward a Low-Temperature Route for Epitaxial Integration of BiFeO3 on Si
AU - Plokhikh, Aleksandr V.
AU - Karateev, Igor A.
AU - Falmbigl, Matthias
AU - Vasiliev, Alexander L.
AU - Lapano, Jason
AU - Engel-Herbert, Roman
AU - Spanier, Jonathan E.
N1 - Funding Information:
Work at Drexel University was supported primarily by the Office of Naval Research under grant number N00014-15-11-2170. The experiments were partially performed using the equipment of the Resource Center of Probe and Electron Microscopy (Kurchatov Complex of NBICS-Technologies, NRC “Kurchatov Institute”). The authors acknowledge the Centralized Research Facilities at Drexel University for access to XRD (NSF DMR 1040166) and Picosun Oy (Finland) for support. J.L. and R.E.-H. acknowledge support from the National Science Foundation MRSEC Center for Nanoscale Science at Penn State through grant number DMR1420620.
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/5/16
Y1 - 2019/5/16
N2 - Epitaxial thin-film growth enables novel functionalities, particularly if significant barriers to integration with existing technologies, scalability and excessive temperature of films, can be addressed. Here, we demonstrate a step toward addressing both challenges by combining hybrid molecular beam epitaxy and atomic layer deposition to epitaxially integrate BiFeO3 on Si wafers via a SrTiO3 metamorphic buffer layer. The solid-solid transformation of atomic-layer-deposited amorphous Bi-Fe-O films into epitaxial BiFeO3 thin films is investigated by in situ annealing utilizing transmission electron microscopy. The amorphous Bi-Fe-O layer undergoes a very complex crystallization process, encompassing phenomena such as reorientation, recrystallization, and grain growth. Our in situ transmission electron microscopy study revealed that a growth front of epitaxial crystallites emerged from the interface with the (001)-oriented SrTiO3 as temperature increased, whereas randomly oriented BiFeO3 crystallites formed simultaneously away from the interface. Structural rearrangement and recrystallization of crystallites took place at temperatures below 400 °C. At the final stage, above 400 °C, epitaxial crystallites larger than 60 nm merged into a single crystalline film. Our results demonstrate that this approach permits high-quality epitaxial integration of BiFeO3 thin films at back-end-of-line-compatible temperatures below 500 °C on metamorphic SrTiO3 buffer layers on Si.
AB - Epitaxial thin-film growth enables novel functionalities, particularly if significant barriers to integration with existing technologies, scalability and excessive temperature of films, can be addressed. Here, we demonstrate a step toward addressing both challenges by combining hybrid molecular beam epitaxy and atomic layer deposition to epitaxially integrate BiFeO3 on Si wafers via a SrTiO3 metamorphic buffer layer. The solid-solid transformation of atomic-layer-deposited amorphous Bi-Fe-O films into epitaxial BiFeO3 thin films is investigated by in situ annealing utilizing transmission electron microscopy. The amorphous Bi-Fe-O layer undergoes a very complex crystallization process, encompassing phenomena such as reorientation, recrystallization, and grain growth. Our in situ transmission electron microscopy study revealed that a growth front of epitaxial crystallites emerged from the interface with the (001)-oriented SrTiO3 as temperature increased, whereas randomly oriented BiFeO3 crystallites formed simultaneously away from the interface. Structural rearrangement and recrystallization of crystallites took place at temperatures below 400 °C. At the final stage, above 400 °C, epitaxial crystallites larger than 60 nm merged into a single crystalline film. Our results demonstrate that this approach permits high-quality epitaxial integration of BiFeO3 thin films at back-end-of-line-compatible temperatures below 500 °C on metamorphic SrTiO3 buffer layers on Si.
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U2 - 10.1021/acs.jpcc.8b12486
DO - 10.1021/acs.jpcc.8b12486
M3 - Article
AN - SCOPUS:85065889177
VL - 123
SP - 12203
EP - 12210
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 19
ER -