Epitaxial Planarization Using Ion Beam Assisted Deposition

Abstract

ABSTRACTCeO2 thin films have been deposited on patterned (100) LaAlO3 substrates using ion beam assisted deposition (IBAD) with ion beam energies between 350 and 500eV. Deposition temperatures were varied between 400°C and 600°C and deposition rates from 0.2Å/s to 1.2Å/s. Both normal and off-normal incidence ion bombardment have been studied. A trend towards planarization is observed when the ion to atom ratio is adjusted to obtain the proper degree of etching. The planarization mechanism for normal incidence bombardment appears to be similar to that previously observed for bias sputtering. X-ray diffraction shows that an initial layer of evaporated epitaxial CeO2 is required for continued epitaxial development during IBAD processing. The extent of planarization via off-normal ion incidence can be related to the direction of the ion beam with respect to the patterned features. X-ray pole figure measurements show that these films possess an in-plane orientation that is directly related to the ion beam parameters.