Role of the nano amorphous interface in the crystallization of Sb2Te3 towards non-volatile phase change memory: insights from first principles

Abstract

The nano amorphous interface is important as it controls the phase transition for data storage. Yet, atomic scale insights into such kinds of systems are still rare. By first-principles calculations, we obtain the atomic interface between amorphous Si and amorphous Sb2Te3, which prevails in the series of Si-Sb-Te phase change materials. This interface model reproduces the experiment-consistent phenomena, i.e. the amorphous stability of Sb2Te3, which defines the data retention in phase change memory, and is greatly enhanced by the nano interface. More importantly, this method offers a direct platform to explore the intrinsic mechanism to understand the material function: (1) by steric effects through the atomic "channel" of the amorphous interface, the arrangement of the Te network is significantly distorted and is separated from the p-orbital bond angle in the conventional phase-change material; and (2) through the electronic "channel" of the amorphous interface, high localized electrons in the form of a lone pair are "projected" to Sb2Te3 from amorphous Si by a proximity effect. These factors set an effective barrier for crystallization and improve the amorphous stability, and thus data retention. The present research and scheme sheds new light on the engineering and manipulation of other key amorphous interfaces, such as Si3N4/Ge2Sb2Te5 and C/Sb2Te3, through first-principles calculations towards non-volatile phase change memory.

Phase‐Change Superlattice Materials toward Low Power Consumption and High Density Data Storage: Microscopic Picture, Working Principles, and Optimization

“…Moreover, the endurance of the N‐doped superlattice can reach 10 8 cycles, which is better than 10 6 cycles of GST‐SL (Figure o). Since many elements (such as C, N, O, Si, Ag, W, Bi, Sn) have been demonstrated to improve the performance of conventional bulk GST, similar attempts in GST‐SL should be expected.…”

“…As for the growth of superlattice, searching for proper substrates is a valuable subject. As for the control of composition, superlattice can extend to other material systems with low power consumption, such as SiSbTe alloy, GeCuTe alloy, GeSb alloy, TiSbTe alloy, and ScSbTe alloy . Their forms in superlattice should have great chances of further improving PCM performance.…”

“…One direction is to find materials alternative to GST. For example, during the past decades, there emerged several new material candidates for low power consumption including the SiSbTe alloy, the GeCuTe alloy, the GeSb alloy, the TiSbTe alloy, the ScSbTe alloy, the C‐doped GST alloy, the C‐doped GeTe alloy, the N‐doped GST alloy, the N‐incorporated GeTe alloy, the O‐doped GST alloy, and so on …”

The low-temperature heat capacity of the Sb2Te3−xSexsolid solution from experiment and theory

“…Binary main-group V 2 VI 3 chalcogenides, e.g. Sb 2 Te 3 and Bi 2 Te 3 , are narrow-gap semiconductors and have been studied intensively as they are potential candidates for applications in thermoelectric [1,2] and optoelectronic [3] devices as well as for non-volatile phase-change memories [4]. Antimony telluride, Sb 2 Te 3 , crystallizes in a tetradymite structure type with space group R 3m [5].…”

Nucleation Dynamics of Phase‐Change Memory Materials: Atomic Motion and Property Evolution

“…If doped/alloyed with elements that disturb p ‐bonding, such as C, Si, and Cu, the amorphous phase of PCM materials becomes more stable. [ 61–64 ] In contrast, if doped with elements whose bonding is similar with p ‐bonding, such as Ti and Sc, the speed of crystallization is further enhanced due to the formation of the robust seeds of nucleus (i.e., the octahedral motifs). [ 18,65–67 ]…”