SnxSe100-X (15|X|30) alloys have been studied to explore their suitability as phase change materials for nonvolatile memory applications. The phase change characteristics of thin films prepared by a Radio Frequency (RF) magnetron co-sputtering system were analyzed by an X-ray diffractometer and 4-point probe measurement. A phase change static tester was also used to determine their crystallization under the pulsed laser irradiation. X-ray diffraction measurements show that the transition in sheet resistance is accompanied by crystallization. The amorphous state showed sheet resistances five orders of magnitude higher than that of the crystalline state in SnxSe100-X (x = 15, 20, 25, 30) films. In the optimum composition, the minimum time of SnxSe100-X alloys for crystallization was 160, 140, 150, and 30ns at 15mW, respectively. The crystallization temperature and the minimum time for crystallization of thin films were increased by increasing the amount of Sn, which is correlated with the activation energy for crystallization.

Electrical optical switching and structural transformation of Ge15Sb85, Sb65Se35 and N2.0 sccm doped Sb83Si17 were studied to investigate the phase change characteristics for PRAM application. Sb-based materials were deposited by a RF magnetron co-sputtering system and the phase change characteristics were analyzed using an X-ray diffractometer (XRD), a static tester and a four-point probe. Doping Ge, Se or Si atoms reinforced the amorphous stability of the Sb-based materials, which affected the switching characteristics. The crystallization temperature of the Sb-based materials increased as the concentration of the Ge, Se or Si increased. The minimum time of Ge15Sb85, Sb65Se35 and N2.0 sccm doped Sb83Si17 for crystallization was 120, 50 and 90 ns at 12 mW, respectively. Sb65Se35 was crystallized at 170˚C. In addition, the difference in the sheet resistances between amorphous and crystalline states was higher than 104Ω/γ.