MICROSTRUCTURES OF SPUTTERED ORIENTED Si/CeO2 BILAYERs YBa2Cu3O7-δ/Si INTEGRATED MICROELECTRONICS

Abstract

In the framework of a research aimed to superconductor/semiconductor integrated electronics, we have grown a-axis oriented YBa 2 Cu 3 O 7-δ (YBCO) thin films on silicon (100) substrates with (111) oriented insulating buffer layers of cerium dioxide ( CeO 2), using magnetron sputtering deposition techniques. The properties of the cerium dioxide layer have been preliminary optimized by means of several layout and by monitoring the growing procedures through X-ray diffraction, AFM and TEM techniques. The lattice matching between CeO 2 and YBCO resulted to be worsened by an amorphous thin SiO 2 layer at the Si/CeO 2 interface, that decouples the buffer orientation from the seed orientation. However, it was possible to grow a relatively thick, optimally textured layer of CeO 2 without spurious orientations. The YBCO films deposited on top of this layer result preferentially a-axis oriented. The transition widths are very large, jet well controllable and reproducible. Some technological applications can be already envisaged.