2017 Volume 66 Issue 9 Pages 648-653
The crystallization of GeBiTe (GBT) is faster than that of the well-known phase-change recording material GeSbTe (GST). Therefore, the investigation of GBT structure as well as its crystallization process is attractive. Accordingly, the high-speed crystallization of GBT is due to Bi. Thus, it was necessary to know the local structure around Bi within the amorphous GBT. Note that an interface layer, which is a very thin dielectric film adjacent to recording film, assists the crystallization of phase-change material in the optical recording media. The local structure around Bi in GBT within an actual media was analyzed using XAFS. Bi LIII-edge XAFS spectra of crystalline and amorphous GBT respectively, both with and without interface layer in the media, were obtained. As result of this analysis on GBT, nearest neighbor atom of Bi was found to be Ge. Moreover, within the amorphous GBT, the interatomic distance around Bi is larger than that around Ge. These are the differences between GST and GBT. We speculate that these factors contribute to the improvement of the GBT crystallization speed. On the other hand, the interface layer doesn’t influence the local structure of GBT; however, it does have an electric effect on the recording layer.
