Study of the growth and annealing conditions of SrCu2O2 (SCO) thin films deposited by injection MOCVD

Abstract

AbstractDivalent ions in a copper oxide matrix M2+Cu2O2 have been intensively studied for the application field of p‐type transparent conductive oxides (TCOs) in order to achieve transparent electronic devices. In this paper, we are presenting our study of the growth and annealing conditions of SrCu2O2 (SCO) thin films deposited by injection metalorganic chemical vapor deposition (MOCVD) apparatus. Limited work has been performed using MOCVD in spite of the high facility to prepare different ratios of precursors, large‐area deposition and high deposition rate. The precursors for this study were strontium and copper tetramethylheptadionate (TMHD) and the solvent used was meta‐xylene. Fourier transform infrared (FTIR) and X‐ray diffraction (XRD) analyses have shown that the as‐deposited films in the temperature range (480–570 °C) were composed of a mixture of copper oxide (CuO) and strontium carbonate (SrCO3), which is due to the low‐temperature deposition. Post‐deposition treatment was needed to achieve the SCO compound. So, different rapid thermal annealing (RTA) conditions were studied. The RTA under Ar gas is too reductive and metallic copper is clearly visible on the surface. On the other hand, RTA under O2 partial pressure provokes the combustion of carbonate and the crystallisation of SrCu2O3 phase at temperatures above 550 °C as observed by FTIR and XRD measurements. Once this phase is obtained, a final RTA under pure Ar leads to the SCO phase at temperatures higher than 600 °C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)