| AVS 60th International Symposium and Exhibition | |
| Thin Film | Friday Sessions |
| Session TF+EM+NS+SS-FrM |
| Session: | Thin Film: Growth and Characterization III |
| Presenter: | H. Wang, Brigham Young University |
| Authors: | H. Wang, Brigham Young University R. Gates, Brigham Young University B. Lunt, Brigham Young University M. Asplund, Brigham Young University S. Vaithiyalingam, Pacific Northwest National Laboratory R.C. Davis, Brigham Young University M.R. Linford, Brigham Young University |
| Correspondent: | Click to Email |
We have prepared a novel write–once–read–many (WORM) optical stack on Mylar tape as a replacement for magnetic tape. This approach has the potential to substantially increase the longevity of tape data storage, which is extremely important for many large organizations. This work follows our efforts to develop an archival DVD that will last 1000 years (see www.mdisc.com ). This optical tape is modified with a ca. 40 nm write layer prepared by co-sputtering bismuth and a tellurium–selenium alloy target to prepare a bismuth-tellurium-selenium (BTS) write layer. This film is sandwiched between thin, protective films of reactively sputtered carbon. The adhesion of this stack to the substrate has been confirmed. Film thicknesses were determined by AFM step height measurements and film composition, morphology, and chemistry were confirmed by RBS, XPS, ToF-SIMS, and SEM. Sub 3 um marks can be made on the Mylar/C/BTS/C tape using 532 nm laser pulses. No marks are observed on the uncoated (control) Mylar substrate under identical conditions. Marks, which showed craters/movement of the write material, were characterized by optical microscopy and atomic force microscopy (AFM). The threshold power for marking the tape was explored as a function of film thickness. Interestingly, the threshold power is higher for either thinner or thicker films and lowest for films of intermediate thicknesses. These results are attributed to a tradeoff between lower optical absorption by thinner films and the requirement of higher powers to melt thicker films. The BTS films appear to be quite stable to storage in the air. The effects of the microscope objective in our home-built apparatus were explored and smaller, higher quality marks could be made with the 60X objective compared to the 40X. The write process to the film was modeled by COMSOL, and the simulation was consistent with experimental results.