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

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_0.67Sr_0.33MnO₃ monolayers on pseudosubstrates SrTiO₃(100)/Si at high temperature. We show that using the ratio of reflectance for the two different polarizations (s,p) R_p/R_s = tan²ψ 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).