A STUDY OF H-2 MIGRATION AND RELEASE IN H-2(-IRRADIATED YBA2CU3O7-DELTA())LAALO3 (100) SAMPLES DURING RAPID THERMAL ANNEALING/

A c-axis oriented YBa2Cu3O7-delta (YBCO) film, approximately 190 nm th ick, deposited onto [100] LaAlO3 by DC sputtering was irradiated at ro om temperature with 50-keV H-2+ to a dose of 1 x 10(16) ions cm-2. The as-implanted sample was divided into several pieces and annealed in a flowing oxygen ambient using rapid thermal annealing (RTA), at variou s temperatures between 450 and 900-degrees-C. RTA at 450-degrees-C for 20 s results in the fast diffusion of H-2 out of the film (i.e. the a pparent diffusion coefficient is estimated to be larger than 2 x 10(-1 1) cm2/s) but no obvious change is seen in the distribution of H-2 in the substrate. All of the trapped H-2 in the substrate is found to mig rate out the sample after RTA at 900-degrees-C for 2 min. After 20 s i sochronal RTA at temperatures between 450 and 900-degrees-C, the relat ive release fraction of H-2 from the substrate increases near-linearly with increasing anneal temperature. The activation energy (temperatur e) for H-2 release from the weaker traps in the irradiated substrate i s estimated to be approximately 1.6 eV (500-degrees-C). There are stro nger traps in the irradiated substrate, with the activation energy (te mperature) for H-2 release from them being estimated to be larger than 2.3 eV (800-degrees-C). The behaviour of implanted H-2 during RTA can be explained by the mechanism of H-2 detrapping and re-trapping.