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采用射频磁控溅射方法制备了两种用于相变存储器的Ge1Sb2Te4和Ge2Sb2Te5相变薄膜材料,对其结构、电学输运性质和恒温下电阻随时间的变化关系进行了比较和分析.X射线衍射(XRD)和原子力显微镜(AFM)的结果表明:随着退火温度的升高,Ge1Sb2Te4薄膜逐步晶化,由非晶态转变为多晶态,表面出现均匀的、高度起伏小于10nm的突起;而对于Ge2Sb2Te5薄膜样品,其结构也从非晶态向多晶态转变,但表面形貌的变化不太明显.霍尔效应测量结果表明,无论是原始淀积的还是退火的样品,Ge1Sb2Te4薄膜的载流子浓度均比Ge2Sb2Te5高三个数量级以上,由此推论:Ge1Sb2Te4较高的电导主要来自其较大的载流子浓度.利用变温探针台测量了Ge1Sb2Te4和Ge2Sb2Te5在相变前恒温条件下电阻随时间变化关系,结果表明在相同的恒温条件下Ge2Sb2Te5电阻保持时间更长,更加有利于数据的存储.
Two kinds of Ge1Sb2Te4 and Ge2Sb2Te5 phase-change materials were prepared by radio-frequency magnetron sputtering, and their structures, electrical transport properties and resistance at constant temperature were compared and analyzed with time.X-ray The results of X - ray diffraction (XRD) and atomic force microscopy (AFM) showed that the Ge1Sb2Te4 thin films crystallized gradually from amorphous to polycrystalline with the increase of annealing temperature. For Ge2Sb2Te5 thin films, the structure changes from amorphous state to polycrystalline state, but the change of surface morphology is not obvious. The results of Hall effect measurements show that the Ge1Sb2Te4 thin films, whether originally deposited or annealed, Carrier concentration higher than that of Ge2Sb2Te5 by more than three orders of magnitude, thus infer: the higher conductivity of Ge1Sb2Te4 mainly comes from its larger carrier concentration.Using the temperature probe station to measure the resistance of Ge1Sb2Te4 and Ge2Sb2Te5 before the phase transition temperature The results show that the resistance of Ge2Sb2Te5 is kept longer under the same constant temperature condition, which is more conducive to data storage.