Epitaxial Growth of CeO₂ Films on Si(111) by Sputtering

Abstract

CeO2 films were epitaxially grown on Si(111) substrates by reactive sputtering following the single-crystal CeO2 seed layer formation by oxygen-reactive solid-phase epitaxy. Formation of metallic Ce layers and oxidation of the layers prior to reactive sputtering was found to be the key process for epitaxial growth of CeO2 on Si substrates. An Auger electron spectroscopy depth profiling analysis showed that the Ce–Si interlayer was formed after the Ce metal deposition. Reflection high-energy electron diffraction and transmission electron microscopy proved that epitaxial CeO2 films were grown by reactive sputtering on the seed layers formed by oxidation of Ce metal layers with thickness of 5 to 10 nm. Crystalline quality of the films depended on the sputtering conditions, especially on total sputtering pressure and oxygen concentration. The optimization of the conditions for seed layer formation by oxygen-reactive solid-phase epitaxy and reactive sputtering was an important factor for improving the crystalline quality of epitaxially grown CeO2 film.

Raman characterization before and after rapid thermal annealing of CeO2 thin films grown by rf sputtering on (111) Si

“…1). This result is in agreement with many reports dealing with the deposition of CeO 2 on a (111) Si substrate, realized by e-beam evaporation, [1] sputtering, [5] using low-energy dual-beam deposition technology [6] or laser ablation. [7] CeO 2 powder used to fabricate the targets and CeO 2 targets were characterized by RS (Fig.…”

Charge storage in CeO2/Si/CeO2/Si(111) structures by electrostatic force microscopy

“…This attractive set of properties has the potential to lead to a fully functional silicon heterojunction technology. A significant amount of work has been done examining the growth and characterization of CeO 2 crystals on Si, [1][2][3][4][5] and the growth of single crystal Si on to CeO 2 /Si heterostructures 6 has been recently reported. Based on these promising results, a silicon resonant tunneling diode, an improved silicon-on-insulator technology, and stacked silicon electronics have all been proposed.…”

Orientation selective epitaxial growth of CeO2 layers on Si(1 0 0) substrates using reactive DC magnetron sputtering with substrate bias

“…Epitaxial growth of CeO 2 layers was accompanied by simultaneous oxidation of the underlying Ce-silicide layer. The two-step growth method similar to this study has already been reported in growing epitaxial CeO 2 (1 1 1)/Si(1 1 1) structures [6], but our method is different from theirs in the points of the use of a very thin metallic Ce layer and not having an intentional oxidation process before CeO 2 deposition but having a silicidation process before CeO 2 layer deposition.…”

“…For applications to silicon technology, epitaxial growth of CeO 2 thin films on Si substrates has been studied, where a great deal of effort has been devoted to make use of close epitaxial relations of CeO 2 with silicon: both materials have cubic symmetry and a lattice mismatch parameter between them is a very small value of 0.35%. Epitaxial growth of CeO 2 layers on Si substrates has been studied for the application to microelectronics [1][2][3][4][5][6][7][8][9]. Although CeO 2 (1 1 1) layers grow on Si(1 1 1) substrates at very low temperatures, such as room temperature with excellent crystallinity [1][2][3][4][5][6][7], epitaxial growth on Si(1 0 0) substrates requires higher growth temperature and has strong tendency to grow with (1 1 0) orientation [1,8,10].…”

“…Epitaxial growth of CeO 2 layers on Si substrates has been studied for the application to microelectronics [1][2][3][4][5][6][7][8][9]. Although CeO 2 (1 1 1) layers grow on Si(1 1 1) substrates at very low temperatures, such as room temperature with excellent crystallinity [1][2][3][4][5][6][7], epitaxial growth on Si(1 0 0) substrates requires higher growth temperature and has strong tendency to grow with (1 1 0) orientation [1,8,10]. Much efforts have been devoted in obtaining single crystalline (1 1 0)-layers by preventing double domain structure formation using miscut substrates and lowering of epitaxial growth temperature by electron beam assistance during evaporation [11][12][13].…”