Atomic scale insight into the effects of Aluminum doped Sb2Te for phase change memory application

Abstract

To date, the unpleasant trade-off between crystallization speed and thermal stability for most phase change materials is detrimental to achieve phase change memory (PCM) with both features of high-speed and good-retention. However, it is proved that Al doping in Sb2Te, served as storage media in PCM, favors both a high writing speed (6 ns) and a good retention (103 °C), as well as a low power consumption. Judging by experimental and theoretical investigations, doped Al atoms prefer to replace Sb in Sb2Te lattice, strongly bonded with 6 Te atoms, to form a homogeneous phase. While in amorphous Al doped Sb2Te (AST), Al atoms are in tetrahedral environment, firmly bonded with four Sb/Te atoms. The strong bonding in Al centered tetrahedron in amorphous AST can obstruct the collective motion of Sb atoms near the matrix boundary, leading to the improvement in thermal stability and the confinement in grain size.

Investigation of etching selectivity and microstructure of Ag-doped Sb2Te thin film for dry lithography

“…However, the peak B is separated into C and D after laser exposure. The peak C located at ∼131 cm −1 is attributed to the A 1g mode of homopolar Sb-Sb bonds while the peak D located at ∼153 cm −1 is owing to the A 1g 2 mode in Sb 2 Te 3 quintuple layers [31]. The results imply that laser irradiation leads to the generation of new Sb-Sb bonds, in good agreement with the XRD results.…”

“…For the as-deposited Ag 1.44 Sb 2.19 Te film, two obvious Raman peaks labeled as A and B are observed at ∼113 and ∼145 cm −1 , respectively. The peak B can be ascribed to the vibration of amorphous Sb-Te bonds whereas the peak A is due to the E g mode of homopolar Sb-Sb bonds [30,31]. However, the peak B is separated into C and D after laser exposure.…”

Realization of Selector‐Memory Bi‐Functionality with Self‐Current Regulation Utilizing Poly‐Crystalline Based GST Electrolyte for Memristor Hardware Development

“…The higher intensity of three peaks in the RTA sample compared to the As‐DEP sample suggests the presence of smaller grains in GST film. [ 42 ] Figure 1c,d show energy‐dispersive spectroscopy (EDS) line scan and mapping images of the RTA sample. The GST composition ratio without Ag was confirmed to be close to Ge:Sb:Te = 2:2:5 (Ge, 22.2%; Sb, 23.9%; Te, 53.9%), as shown in Figure 1c.…”

First-principles study of the liquid and amorphous phases of Sb2Te phase change memory material

“…fraction of octahedrons, which enhances the thermal stability of amorphous C-GeTe [74] and C-GeSb [75]. The Alcentered tetrahedrons are introduced into amorphous Sb 2 Te, while Al atoms tend to occupy octahedral sites in the crystal phase, resulting in obvious local structural difference, thus a higher crystallization temperature of Al-Sb 2 Te [76]. Similarly, the Ge-centered tetrahedrons are suggested to be the structural origin of higher amorphous stability of Ge-Sb [77].…”