R.F. sputtering of Sr 2Nb 2O 7

Abstract

The deposition of Sr 2Nb 2O 7 thin films by conventional r.f. sputtering has been shown to give rise to films with stoichiometry different from that of the target material. The composition offset was traced to an anomalously high resputtering rate from the substrate which occurs for argon, argonoxygen or pure oxygen carrier gases. By suitably adjusting target composition at a fixed sputtering geometry and power level, stoichiometric films were produced. For films deposited onto substrates at temperatures of up to 1100 °C the Sr 2Nb 2O 7 was X-ray amorphous and showed simple linear dielectric properties with no evidence of the ferroelectricity of the corresponding crystalline form. High temperature annealing disrupted the integrity of the film before the crystalline form could be clearly identified.