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采用聚焦脉冲激光研究了Ge2Sb2Te5薄膜在沉积和激光淬火两种非晶态下反射率与激光脉冲宽度变化的关系,发现沉积态的Ge2Sb2Te5薄膜在晶化触发阶段内的反射率随激光脉冲宽度增加而减小,经过激光淬火的非晶态Ge2Sb2Te5薄膜在晶化触发阶段内的反射率随激光脉冲宽度增加而变化平缓.本文借用气-液体系中过饱和度分析液滴形成的原理,从统计物理学角度详细研究了两种非晶态Ge2Sb2Te5薄膜在脉冲激光作用下的晶化过程及机理,结果表明,当Ge2Sb2Te5的非晶态程度处于未饱和或饱和状态时不形成晶核;当Ge2Sb2Te5的非晶态程度处于过饱和状态时,此时的Ge2Sb2Te5为亚稳态,可能形成大小不等的晶核,但只有半径大于临界晶核尺寸时才可能长大成晶粒.而应力降低晶化能垒,增加非晶态Ge2Sb2Te5的过饱和度是导致沉积态与激光淬火态的Ge2Sb2Te5薄膜在晶化触发阶段内反射率随激光脉冲宽度变化规律不一致的根本原因,并据此解释了Ge2Sb2Te5薄膜在这两种状态下的反射率随激光脉冲宽度的变化特点及规律. 相似文献
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Bomy CHEN 《材料科学技术学报》2005,21(1):95-99
The amorphous Ge2Sb2Te5 film with stoichiometric compositions was deposited by co-sputtering of separate Ge, Sb, and Te targets on SiO2/Si (100) wafer in ultrahigh vacuum magnetron sputtering apparatus. The crystallization behavior of amorphous Ge2Sb2Te5 film was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). With an increase of annealing temperature, the amorphous Ge2Sb2Te5 film undergoes a two-step crystallization process that it first crystallizes in face-centered-cubic (fcc) crystal structure and finally fcc structure changes to hexagonal (hex) structure. Activation energy values of 3.636±0.137 and 1.579±0.005 eV correspond to the crystallization and structural transformation processes, respectively. From annealing temperature dependence of the film resistivity, it is determined that the first steep decrease of the resistivity corresponds to crystallization while the second one is primarily caused by structural transformation from 相似文献
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溅射功率对Ge2Sb2Te5薄膜光学常数的影响 总被引:1,自引:0,他引:1
研究了溅射功率对Ge2Sb2Te5薄膜的光学常数与波长关系的影响。结果表明,在波长小于500nm的情况下,随溅射功率的增加非晶态薄膜的折射率n先增加然后减小,消光系数k则逐渐减小;在波长大于500nm的情况下,随溅射功率的增加折射率n逐渐减少,消光系数k先减小后增加。对于晶态薄膜样品,在整个波长范围折射率n随溅射功率的增加减小后增加,消光系数k则逐渐减少。薄膜样品的光学常数,在长波长范围随波长变化较大,在短波长范围变化较小。讨论了溅射功率对Ge2Sb2Te5薄膜的光学常数影响的机理。 相似文献
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研究了激光辐照引起Ge2Sb2Te5非晶态薄膜的电/光性质变化, 当激光功率为580mW时薄膜的方块电阻有四个数量级(107~103Ω/□)的突变; 对电阻发生突变前、中、后的三个样品进行了XRD测试, 结果表明, 随着激光功率的增大,薄膜由非晶态向晶态转变,用椭偏仪测试了结构转变前、中、后三个样品的光学常数, 在可见光范围内薄膜的光学常数在波长相同情况下有: n非晶态>n中间态>n晶态, k晶态>k中间态>k非晶态, α晶态>α中间态>α非晶态, 结合电阻变化曲线和XRD图谱讨论了激光辐照Ge2Sb2Te5非晶态薄膜的电/光性质变化同激光功率和结构转变之间的关系. 相似文献
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采用聚焦脉冲激光研究了Ge2Sb2Te5薄膜在沉积和激光淬火两种非晶态下反射率与激光脉冲宽度变化的关系,发现沉积态的Ge2Sb2Te5薄膜在晶化触发阶段内的反射率随激光脉冲宽度增加而减小,经过激光淬火的非晶态Ge2Sb2Te5薄膜在晶化触发阶段内的反射率随激光脉冲宽度增加而变化平缓。本文借用气-液体系中过饱和度分析液滴形成的原理,从统计物理学角度详细研究了两种非晶态Ge2Sb2Te5薄膜在脉冲激光作用下的晶化过程及机理,结果表明,当Ge2Sb2Te5的非晶态程度处于未饱和或饱和状态时不形成晶核;当Ge2Sb2Te5的非晶态程度处于过饱和状态时,此时的Ge2Sb2Te5为亚稳态,可能形成大小不等的晶核,但只有半径大于临界晶核尺寸时才可能长大成晶粒,而应力降低晶化能垒,增加非晶态Ge2Sb2Te5的过饱和度是导致沉积态与激光淬火态的Ge2Sb2Te5薄膜在晶化触发阶段内反射率随激光脉冲宽度变化规律不一致的根本原因,并据此解释了Ge2Sb2Te5薄膜在这两种状态下的反射率随激光脉冲宽度的变化特点及规律。 相似文献
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Toshihisa Nonaka Gentaro Ohbayashi Yoshiharu Toriumi Yuji Mori Hideki Hashimoto 《Thin solid films》2000,370(1-2):258-261
Direct X-ray diffraction measurement of the erased state of the Ge–Sb–Te recording layer in a four-layered phase change optical disk, which was produced by an optical disk drive, was performed. It was identified as an fcc crystal structure. In order to carry out the detailed crystal structure analysis by the powder X-ray diffraction method with Rietveld refinements, somewhat larger amount of the fcc crystal powder was prepared from deposited 10 μm thick films. It revealed that Ge2Sb2Te5 belongs to the NaCl type structure (Fm
m) with the 4a site including 20% vacancies. The conclusion was supported by the results of the density measurements with Grazing Incidence of X-ray Reflectivity. 相似文献
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