Influence of target-substrate distance and oxygen pressure on morphology, orientation and homogeneity of laser-deposited YBa2Cu3O7 films on MgO (100)

✍ Scribed by F. Goerke; A. Thorns

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 658 KB
• Volume: 251
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(95)00333-9

✦ Synopsis

A pulsed KrF excimer laser is used to deposit YBa2Cu30 7 films on MgO (100). We report on the influence of target-substrate distance, oxygen pressure and substrate temperature in the range of 30 to 100 mm, 0.03 to 0.4 mbar and 732 to 800°C, respectively. The film quality is characterized by electrical properties, homogeneity, orientation and morphology. At the pressure of 0.4 mbar we obtain optimum electrical and morphological properties for a target-substrate distance of about 46 mm. The homogeneity can be improved by increasing the target-substrate distance. In order to maintain smooth surfaces, it is necessary to decrease the oxygen pressure. A sensitive influence of the oxygen pressure on the orientation is observed, when the pressure is reduced below 0.1 mbar, i.e. a smaller offer of oxidized elements seems to favor a-axis orientation. Optimum deposition parameters for the target-substrate distance of 100 mm are found to be the oxygen pressure of 0.07 mbar and the substrate temperature of 765°C.