Li Tao

Shanghai Institute of Microsystem And Information Technology · PCRAM

Mo, as a dopant, is doped into SbTe to improve its thermal stability. It is shown in this paper that the Mo-doped Sb 2 Te 3 (Mo 0.26 Sb 2 Te 3 , MST) material possesses phase change memory (PCM) applications. MST has better thermal stability than Sb 2 Te 3 (ST) and will crystallize only when the annealing temperature is higher than 250 °C. With the...

In the semiconductor industry, doping modification is a common and effective method to regulate the properties of materials. For Ge2Sb2Te5 (GST) phase change materials, incorporation with nitrogen has been widely reported due to improvement in its thermal stability and reduction in its power consumption. However, whether in amorphous or crystalline...

Transition metal elements doping can greatly improve the usability of Sb–Te for phase change memory. In this paper, we focused on the thermal stability of transition vanadium (V)-doped Sb2Te (VSb2Te) films with different V concentration which were prepared by co-sputtering. The effects of V doping on the crystallization and microstructure propertie...

Selectors are a crucial component of establishing high-density, massive, three-dimensional (3D) stackable novel non-volatile memories and neural networks. Although a lot of work has been done to develop new selectors, it is still a considerable difficulty to obtain selectors with ultra-high ON-state current to meet the actual device requirements, e...

Doping is indispensable to tailor phase-change materials (PCM) in optical and electronic data storage. Very few experimental studies, however, have provided quantitative information on the distribution of dopants on the atomic-scale. Here, we present atom-resolved images of Ag and In dopants in Sb2Te-based (AIST) PCM using electron microscopy and a...

Phase change memory (PCM) has great potential for the next-generation nonvolatile memory technology. However, the commonly used Ge2Sb2Te5 (GST) alloy has poor thermal stability and short device lifetime. Here, we report a carbon-doped GST (CGST) with excellent thermal stability, reduced Reset current (0.6 mA) and longer cycle lifetimes (>10⁸ cycles...

Ovonic threshold switching (OTS) selector is a key technology for high-density crossbar memory array. The basic characteristics of GeSe OTS material including structural information, film properties, microscopic properties, and electrical threshold switching behaviors are investigated by combining ab-initio molecular dynamics and experiments. Amorp...

We propose Y 0.03 (Sb 2 Te) 0.97 (YST), prepared by magnetron sputtering, as a phase-change material for the application in phase change memory (PCM). The thermal stability of Sb 2 Te is increased by Y doping, with the crystallization temperature and 10-year data retention increase from 148.7 °C to 187.7 °C and from 55.0 °C to 114.5 °C, respectivel...

Phase change memory (PCM) with advantages of high operation speed, multilevel storage capability, spiking-time-dependent plasticity, etc., has wide application scenarios in both Von Neumann systems and neuromorphic systems. In the automotive application, intelligent system not only needs high efficiency to handle massive data processing, but also g...

Phase change materials along the GeTe-Sb isoelectronic tie line are proved to be promising host material for optimization, based on which the well-known golden composition is developed. Here, Sc doped Ge2Sb1Te2 has been proposed for phase change memory (PCM) application, showing higher thermal stability and faster operation speed than those of the...

Phase change memory is widely considered as the most promising candidate as storage class memory (SCM), bridging the performance gaps between dynamic random access memory and flash. However, high required operation current remains the major limitation for the SCM application, even after using defect engineering materials, for example, Ti-doped Sb2T...

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 go...

The contradictory nature between transition speed and thermal stability of phase change materials has always been the key limitation to achieve wide applications under the harsh condition. Ge2.3Sb2.0Te phase change alloy is proposed here to feature high thermal stability (10-year data retention above 220 oC) and fast switching speed (SET programmin...

Phase change random access memory (PCRAM) has gained much attention as a candidate for nonvolatile memory application. To develop PCRAM materials with better properties, especially to draw closer to dynamic random access memory (DRAM), the key challenge is to research new high-speed phase change materials. Here, Scandium (Sc) has been found it is h...

Mo-doped Sb1.8Te materials and electrical devices were investigated for high-thermal-stability and high-speed phase-change memory applications. The crystallization temperature (tc = 185 °C) and 10-year data retention (t10-year = 112 °C) were greatly enhanced compared with those of Ge2Sb2Te5 (tc = 150 °C, t10-year = 85 °C) and pure Sb1.8Te (tc = 166...

To bridge the gap of access time between memories and storage systems, the concept of storage class memory has been put forward based on emerging nonvolatile memory technologies. For all the nonvolatile memory candidates, the unpleasant tradeoff between operation speed and retention seems to be inevitable. To promote both the write speed and the re...

The local structure change of Ge induced by carbon doping in as-deposited Ge2Sb2Te5 films were studied by extended X-ray absorption fine structure and Raman spectrum. Ge-C bonds are formed at the expense of reducing the coordination of Ge-Ge and Ge-Te bonds, and make the local structure of Ge to be a well-defined tetrahedral geometry, which increas...

A memory cell composed of a selector device and a storage device is the basic unit of phase change memory. The threshold switching effect, main principle of selectors, is a universal phenomenon in chalcogenide glasses. In this work, we put forward a safe and controllable method to prepare a SiGeAsTeN chalcogenide film by implanting As ions into spu...

Carbon-doped Sb-rich Ge-Sb-Te (Sb-CGST) is proved to be a promising candidate for phase change memory because of it high crystallization temperature (higher than 200°C) and 10-year data retention temperature (higher than 120°C). The carbon-doped Sb-rich Ge-Sb-Te (Sb-CGST) films were deposited on SiO2/Si (100) substrate by RF magnetron co-sputtering...

The optical properties and structural variations of silicon (Si) doped Sb2Te (SST) films as functions of temperature (210–620 K) and Si concentration (0–33%) have been investigated by the means of temperature dependent Raman scattering and spectroscopic ellipsometry experiments. Based upon the changes in Raman phonon modes and dielectric functions,...