A morphological growth model for laser ablated Y1Ba2Cu3O7−x thin films

✍ Scribed by J. Borck; S. Linzen; K. Zach; P. Seidel

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 547 KB
• Volume: 213
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90769-m

✦ Synopsis

The aim of this work was to investigate the growth mechanism of thin Y tBa2Cu3OT_x films ablated by LPVD. The Y iBa2CU3OT_x films were prepared by KrF-excimer laser ablation (248 nm) on SrTiO3 (100) substrates. To investigate film properties like surface morphology, epitaxy, c-axis length, critical current density jc (77 K) and critical temperature T~ *fr we varied the ablation parameters: target substrate distance dr--s, oxygen partial pressure Po2, substrate temperature Ts and laser energy density L To analyze the films X-ray diffraction, Rutherford backscattering spectroscopy, scanning electron microscopy and electrical measurements were used. Three morphological images (zones) of the YIBa2Cu30~_~ film growth in dependence on Po~ and 7", can be distinguished and the growth model of Thornton can be applied as a general rule for optimization of Y~Ba2Cu3OT_x thin film growth. In a medium zone (zone T in the Thornton model) ofpo~ -~ 70 Pa and T,~ 720°C with dx_s=4 cm and •=4.3 J/cm 2 we get smooth, epitaxial films with T°n> 90 K andj¢ (77 K) > 3× 106 A/cm 2. At high Po2, high dT-s and low/we found outgrowths on the films which are of the same stoichiometry as the surrounding film material.