In situ real-time studies of oxygen incorporation in complex oxide thin films using spectroscopic ellipsometry and scattering and recoil spectrometry

摘要

The surface termination of c-axis oriented YBa{sub}2Cu{sub}3O{sub}(7-δ)(YBCO) and the oxygen incorporation mechanism has been investigated using a unique combination of spectroscopic ellipsometry (SE) and time of flight ion scattering and recoil spectrometry (TOF-ISARS). The high surface sensitivity of the ToF-ISARS technique combined with the bulk oxygen sensitivity of SE are shown to yield complimentary information. The SE provided the film orientation and quality, while ToF-ISARS supplied surface compositional and structural information and enabled isotopic 18{sup left}O tracer studies. It was determined that the O content of the film had little effect on the surface termination of the film, indicating a lack of labile Cu(1) sites at the c-axis oriented YBCO surface. Also, strong evidence for a Ba or BaO terminated structure is shown. The data related to the 18{sup left}O tracer studies indicate that O from the reaction ambient incorporates only into the labile Cu(1) sites during both deposition and annealing, while stable O sites were populated with O from the sputtered target, indicating either the need for sputtered atomic O or sputtered YCuO complexes to occupy the stable Cu(2) sites.