机械-化学耦合作用下GeSbTe相变材料的微观损伤行为

Micro-Damage Behavior of GeSbTe Phase Change Materials Under Mechanical-Chemical Coupling Effect

为了研究机械磨损、化学腐蚀对锗锑碲(GeSbTe)相变材料微观损伤行为的影响,利用原子力显微镜(AFM)及SiO2探针对GeSbTe表面在不同工况下产生的微观损伤进行了研究。实验结果表明:在大气环境下,GeSbTe表面经过单次面磨损(面扫描)会形成一个方形磨坑。该磨坑在NaOH碱性溶液中会发生腐蚀,同时磨坑深度随腐蚀时间增加而增加。在NaOH溶液中对GeSbTe表面进行单次面磨损同样产生方形磨坑,并且该磨坑深度也随腐蚀时间的增加而增加。由大气环境下不同法向载荷磨损对比实验可知,腐蚀前的机械作用会促进后续腐蚀损伤。GeSbTe表面自然氧化层的腐蚀实验表明GeSbTe表面自然氧化层在NaOH溶液中的腐蚀可忽略,并且对GeSbTe次表层起掩膜作用。由于NaOH溶液中SiO2探针与GeSbTe表面存在润滑及双电层作用,致使面磨损损伤较轻微,即对表面自然氧化层的损伤小,导致后续腐蚀损伤轻微。本研究结果有助于理解GeSbTe的化学机械抛光(CMP)机理。

In order to investigate the influence of the mechanical wear and chemical corrosion on the microscopic damage behaviors of GeSbTe phase change materials,the microscopic damage of the GeSbTe surface under different operating conditions were researched by using the atomic force microscope(AFM)and SiO2 probe.The experimental results show that a square wear scar would form on the GeSbTe surface after the single surface wear(surface scan)in the atmosphere.When the wear scar was corroded in the NaOH solution,and the wear scar depth would gradually increase with the increase of the corrosion time.Meanwhile,a square wear scar would also form on the GeSbTe surface after the single surface wear in the NaOH solution,and the wear scar depth would also gradually increase with the corrosion time.According to the wear comparative experiments under different normal loads in atmospheric environment,it indicates that the mechanical action before the corrosion promotes the following corrosion damage.Moreover,the corrosion experiments of the native oxide layer on the GeSbTe surface show that the corrosion of the native oxide layer on the GeSbTe surface in the NaOH solution can be negligible.As a result,the oxide layer can play a role of the mask on the subsurface layer of the GeSbTe.Due to the lubrication and electrical double-layer effect between the SiO2 probe and GeSbTe surface in the NaOH solution,the damage of the wear on the surface is slight,i.e.the damage of the native oxide layer on the surface is slight.Then the following corrosion damage would be slight.The result of this research is helpful to understand the chemical mechanical polishing(CMP)mechanism of GeSbTe.