Akihira Miyachi

We have studied crystal and surface structures of GeSbTe (GST) film using XRD (X ray diffraction) and UHV nc-AFM (Ultrahigh vaccum noncontact mode atomic force microscopy), and have also studied a phase-change controlability of the lateral type GST phase change resistor. As the experimental results, we obtained some knowledge as follows: (1) In annealing process, crystallizing of GST film is FCC structure over 150℃ and then to HEX structure over 335℃ using XRD spectra. (2) Observations of the GST film surfaces have been done by UHV nc-AFM. The observation made it clear that the grain sizes and roughness of the film change before and after annealing. (3) The controlability depends on the phase change resistor size, especially, length and film thickness. (4) The critical phsase change power was 1 or 2 orders magnitude of smaller than the vertical type phase change resistor.