Improved thermal stability of Sb materials by SiO2 doping for ultra-fast phase change memory application
摘要:
Thin fifilms of (SiO2)xSb1-x (x ¼ 0.22, 0.28, 0.36, 0.40) were deposited on Si/SiO2 substrate at room temperature via cosputtering SiO2 and Sb pure targets. Sb fifilms were also prepared by sputtering Sb pure target for comparison. The purities of all targets were 99.999% and the thickness was set to 50 nm by controlling the deposited time. The background pressure and work pressure of the sputtering system were 1.0× 10 and 0.4 Pa,respectively. The compositions of the deposited fifilms were determined by means of energy dispersive spectroscopy (EDS). The amorphous-to-crystalline transition was investigated by in situ fifilm resistance measurements under an Ar atmosphere. The crystalline structures of (SiO2)xSb1-x fifilms with different SiO2 content were analyzed by X-ray diffraction (XRD) carried out on a Bruker D8 Advanced diffractometer with Cu ka radiation in the 2q range from 20 to 60, with a scanning step of 0.01 . The surface roughness of the fifilms was evaluated by Atomic Force Microscope (AFM, FMNanoview 1000), which was carried out in the semi-contact mode. The PCM devices based on the SiO2-doped Sb materials were fabricated and the electrical switching property was measured by a Tektronix AWG5012B arbitrary waveform generator and a Keithley 2400 m. A square-shape current pulse was injected into the cell and bypass line using a pulse generator. The current pulse was passed through a digital oscilloscope, which measured the pulse shape and amplitude that was applied to the cell with the series resistance of the oscilloscope.
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