Layer-by-layer growth of cuprate thin films by pulsed laser deposition

Abstract

The pulsed laser deposition technique has been used to deposit, in a layer-by-layer growth mode, superconducting cuprate thin films on (100) SrTiO3 substrates. The films are deposited using a combination of pulsed O2 jet and a continuous source of atomic O, with the average background pressure maintained as low as 1 mTorr. This permits the in-situ monitoring of the growth process using reflection high-energy electron diffraction (RHEED). Before growth of the cuprate films, a thin SrTiO3 buffer layer is homoepitaxially deposited on the substrate to provide an atomically smooth surface. On a smooth surface, the growth of SrTiO3 occurs in a layer-by-layer mode as indicated by the intensity oscillations of the specular spot in the RHEED pattern. Subsequent layer-by-layer growth of a variety of cuprate films, including YBa2Cu3O7-δ (YBCO), La1.85Sr0.15CuO4 (LSCO), Nd1.85Ce0.15CuO4 (NCCO), and SrCuO2 (SCO), has been achieved under appropriate deposition conditions. © 1993.