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Recently, some Perovskite oxides are intensively investigated for a non-volatile resistive random access memory(RRAM) which is a candidate of the future memories. But the switching mechanism of RRAM is still not understood even if it is an intrinsic or an interface effect. Therefore we have investigated electrically and thermally induced properties in the surface and interface region of Cr:SrZrO3-films, which were deposited epitaxially on SrTiO3(100) by pulsed laser deposition. Growth conditions like temperature, oxygen pressure, electrode material, doping rate and so on were varied to optimize the samples. The structural, electronic and chemical properties of Cr:SrZrO3 films were measured by using x-ray diffraction, I-V measurements, x-ray absorption spectroscopy and x-ray photoelectron spectroscopy. When the substrate temperature was increased from 400oC to 700oC in oxygen environments the doped Cr was diffused to the shallow surface area. It is confirmed again from the measurements after the annealing process in different oxygen pressures. The chemical interaction of Cr in films with Zr and O is small but present. The valency of doped Cr on the surface was changed easily with different oxygen environment. In the same way, the movable charge carriers for the resistance switching may be made in Zr 4d states near Fermi level. Some of the doped trivalent ions can substitute Zr4+ ions so that can cause a local distortion in the host lattice. It seems to be related with the movement of charges. We will discuss here about the behavior of Cr-dopant and about the changes of electronic structures of neighboring atoms caused by different growth conditions. This fact is important for studying the interface phenomena between the oxides and the top electrode and the switching mechanism in resistance random access memory. |