Alain J. Kreisler

INFLUENCE OF RAPID THERMAL ANNEALING PARAMETERS ON PROPERTIES OF YBaCuO THIN FILMS SPUTTERED ON POLYCRYSTALLINE ZIRCONIA

Abstract High-Tc YBaCuO thin films have been prepared on polycrystalline ZrO 2 substrates by low temperature r.f. diode sputtering, followed by rapid thermal annealing (RTA). The gas atmosphere during RTA influences the roughness of the films and time/temperature parameters are critical. A Tc ( R = 0) of 85 K has been obtained with c-axis oriented films, but these have low Jc (1500 A.cm −2 at 77 K). Besides, repeated RTA processes are a suitable way to increase the grain size and improve the orientation of the films.

Rapid thermal annealing of YBaCuO thin films sputtered on substrates

Abstract We have determined the rapid thermal annealing (RTA) conditions that optimize both the surface quality and the superconducting properties of YBaCuO films deposited on silicon-based substrates. This process has allowed a very thin nitride layer (45A) to be a good diffusion barrier; silica acting as a sticking layer. A T(onset) in the 87–91 K range has been obtained, with T(R = 0) ∼- 60 K and Jc ∼- 500 A.cm−2 at T(R = 0) 2 . Repeated RTA cycles might by a way to improve these figures.

Thin films of YBaCuO for electronic applications

An overview of applications of YBaCuO thin films is presented emphasizing the RF properties of these high-Tc superconductors and microelectronics uses with silicon-based substrates. The substrates considered include the MOS dielectrics SiO2 and Si3N4, and a low-temperature deposition processing technique for these films followed by post-annealing is detailed. The time of the rapid thermal annealing following film processing is shown to dictate the electrical and structural characteristics of the films. Rapid thermal annealing is shown to be an effective method for manufacturing superconducting films of silicon substrates, although several cycles of the process can block all superconducting properties. The use of alternative buffer layers is considered as a means for protecting against this effect in superconductors composed of silica on silicon nitride.

YBaCuO thin films used as electrical switch or current limiter

We have sthdied the ability of high Te supereonduotors to operate as electrical switches or current limiters . For this purpose, we have usi YBaCuO films, deposit&I on polycrystalline zirconia slabs by various techniques: conventional two-step processes as well as rapid thermal annealing have been consider&1 . The main results are that with a Tc(onset) of 91 K, the variation of the critical current density versus fruency shows that it will be possible to use the films at 50-60 Hz, although we ne&i to improve our low current density films to demonstrate this.

In situ characterization of YBaCuO thin films during rapid thermal annealing

Rapid Thermal Annealing (RTA) is rather unusual in the field of high Tc superconductor processing, in spite of beeing a classical procedure for semiconductor technologies. Nevertheless, when looking at the few results reported on YBaCuO thin films annealed by RTA, this thermal treatment appears as an attractive way, either to increase the efficiency of a diffusion barrier, when substrates such as silicon are used, or as a rapid step to improve YBaCuO grain growth after deposition. The first characterization of YBaCuO thin films during RTA is reported here, based on four probe resistivity measurements. The influence of two parameters are studied: i) the dwell temperature of the RTA cycle, ii) the gas nature during the process.

Microstructure and superconducting properties of Y 1 Ba 2 Cu 3 O 7-δ thin films grown by rapid thermal annealing (RTA) as a function of crystalline structure of zirconia substrates

High-Tc YBaCuO thin films have been prepared on polycrystalline zirconia substrates by low-temperature RF diode sputtering, followed by a rapid thermal annealing. A Tc(R