In situ monitoring of La_0.67Sr_0.33MnO₃ monolayers grown by pulsed laser deposition

Abstract

Integration of functional oxides on silicon is a key issue for the development of oxide-based electronics. For this purpose, monitoring the growth of these materials by an in situ technique becomes essential to control the thickness, the roughness and the oxidation state of the layers. Using a new static optical setup, i.e. with no modulation, we have studied the deposition and the annealing of pulsed-laser deposited La 0.67 Sr 0.33 MnO 3 monolayers on pseudosubstrates SrTiO 3 (100)/Si at high temperature. We show that using the ratio of reflectance for the two different polarizations (s,p) R p /R s ¼ tan 2 c of the optical signal after reflection, we can follow, in situ, the growth of monolayers (ML) with a precision of one unit cell. Also, the growth mode and the annealing process leading to the determination of the activation energy can be precisely controlled. All these results are corroborated by X-ray diffraction (XRD) and atomic force microscopy (AFM). Using this static measurement method, the obtained results are as sensitive as previous reports with, for example, oblique incidence reflectivity difference (OI-RD).

Pulsed Laser Deposition (PLD)

“…Typically connected to the PLD chamber, RHEED systems are often equipped with a differentiated vacuum pumping unit for in situ observations during thin-film deposition under a gaseous ambience [10]. Several other in situ characterization techniques, including low-energy electron diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, coaxial impact collision ion scattering spectroscopy, scanning probe microscope, and optical measurements, such as spectroscopic ellipsometry, have also been implemented in PLD systems [13][14][15][16][17]. Laser molecular beam epitaxy (MBE) (Figure 8.2) [11,12], which couples in situ RHEED observation with PLD for epitaxial growth, has proved to enable real-time growth control at an atomic-layer scale.…”

“…The crystal orientation of the films depended on the background and nitrogen partial pressures as well as growth temperature. TEM observations also revealed that in-plane AlN jj [11][12][13][14][15][16][17][18][19][20] sapphire and [11][12][13][14][15][16][17][18][19][20] AlN jj [11][12][13][14][15][16][17][18][19][20] 6H-SiC were epitaxial relationships between AlN and substrate materials, respectively. Figure 8.17 shows X-ray diffraction scans of AlN films grown on sapphire (0001) and 6H-SiC (0001).…”

Integration of functional oxides on silicon for novel devices

“…In order to investigate the epitaxial mechanism of perovskite film growth on buffer-layered silicon substrate and to clarify how the buffer layers affect the film properties, we have realized the growth of two different functional oxide films on the STO/Si template by two different epitaxy reactor. Firstly 50 nm-thick LSMO films were grown by Pulsed Laser Deposition (PLD) [16]. Secondly 40 nm-thick BTO films were grown using MBE system.…”

Analysis of Ferromagnetic-Multiferroic Interfaces in Epitaxial Multilayers of LSMO and BFO

“…3 As of yet, researchers know very little about how complex interfacial phenomena between layers of the film affect magnetic properties. 1,[6][7] It is necessary to understand how local types of interference at layer boundaries including diffusion of chemical species, deviations from stoichiometry, and lattice mismatch resulting from different lattice parameter between the FM and AFM layer effect bilayer properties in order to fully characterize these heterostructures and utilize them in novel technologies. 6,7 This paper reports on experiments to determine how varying bilayer parameters effect interfacial interactions.…”