In-situ growth of Y1Ba2Cu3O7−x thin films directly on sapphire by temperature-controlled chemical vapor deposition

✍ Scribed by Aiguo Feng; Li Luo; J. Martin; C.J. Maggiore

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 565 KB
• Volume: 193
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(92)90875-d

✦ Synopsis

A temperature-controlled chemical vapor deposition (TC-CVD) process was developed for in-situ growth of highly c-axis orientated YtBa2Cu30~+x (YBCO) thin films directly on sapphire substrates. This new CVD process, for the first time, uses programmable temperature controllers to optimize and tailor the qualities of deposited YBCO films by precisely control the temperatures of substrates and source compounds in predetermined temperature profiles. By employing a substrate temperature (7",) ramping from T,(high) of 825°C to T~ (low) of 735°C during deposition, we were able to grow highest Tc and J¢ YBCO thin films on sapphire without buffer layer. DC transport four point measurement on the as-deposited films gave a Tc~on~t~ at 92 K and Tc(ze~o~ at 84 K. Critical current density of 4x 10 4 A/cm 2 at 77 K and zero magnetic field was obtained for the films. The asdeposited films were also characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).