Role of interfaces on the stability and electrical properties of Ge(2)Sb(2)Te(5) crystalline structures.
Role of interfaces on the stability and electrical properties of Ge(2)Sb(2)Te(5) crystalline structures.
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DOI：
10.1038/s41598-017-02710-3
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发表时间：
2017-06-01
影响因子：
4.6
通讯作者：
Rimini E
中科院分区：
文献类型：
--
作者：
Mio AM;Privitera SMS;Bragaglia V;Arciprete F;Cecchi S;Litrico G;Persch C;Calarco R;Rimini E
GeSbTe基材料具有多种晶相，从无序岩盐到有序空位层的岩盐，再到稳定的三角相。在本文中，我们调查的结构和电气性能的Ge2Sb2Te5的界面上的作用。我们发现，亚稳岩盐相的成核的网站是至关重要的，在确定空位有序和稳定相的演变。通过适当地选择衬底和覆盖层，可以获得成核位点工程，从而促进或阻止岩盐结构中的空位有序化或向三角相的转化。对于在硅（111）上以非晶相沉积的膜，与SiO2衬底（200 °C）的情况相比，空位有序化发生在较低的退火温度（170 °C）下，或者在存在覆盖层（330 °C）的情况下。的成核机制已被解释的界面能。电阻变化约一个数量级已被测量时，从无序的有序岩盐结构，然后到三角相的过渡。控制以显著电阻率对比为特征的结晶相的形成的可能性对于多级相变数据存储的发展具有根本的相关性。
GeSbTe-based materials exhibit multiple crystalline phases, from disordered rocksalt, to rocksalt with ordered vacancy layers, and to the stable trigonal phase. In this paper we investigate the role of the interfaces on the structural and electrical properties of Ge2Sb2Te5. We find that the site of nucleation of the metastable rocksalt phase is crucial in determining the evolution towards vacancy ordering and the stable phase. By properly choosing the substrate and the capping layers, nucleation sites engineering can be obtained, thus promoting or preventing the vacancy ordering in the rocksalt structure or the conversion into the trigonal phase. The vacancy ordering occurs at lower annealing temperatures (170 °C) for films deposited in the amorphous phase on silicon (111), compared to the case of SiO2 substrate (200 °C), or in presence of a capping layer (330 °C). The mechanisms governing the nucleation have been explained in terms of interfacial energies. Resistance variations of about one order of magnitude have been measured upon transition from the disordered to the ordered rocksalt structure and then to the trigonal phase. The possibility to control the formation of the crystalline phases characterized by marked resistivity contrast is of fundamental relevance for the development of multilevel phase change data storage.