Investigations On The Memory Properties Of Binary Telluride Phase-change Materials With Metal Doping

Along with the progress of science and the development of society, products as computers and mobile phones have become indispensable parts of people’s daily lives. Bigger data needs to be stored, and the importance of storage devices with higher efficiency or higher speed is becoming clearer. Disadvantages of the most widely-used high speed storing technology nowadays (Hard Disk and Flash Memory) is revealed. Such as the storing capacity being restricted by size, the durability of data storage, those fields are facing waves of challenges. As we all know, the traditional flash storage technology, whose theory is based on electrical signal, will come to its end one day in the future.We hope to find a storage technology with higher capacity volume ratio, higher reading and writing speed and lower energy consumption. In the past few years, Non-volatile phase change Storage Technology has made very sound progress. As one of non-volatile phase change storage, Phase change memory has huge differences in resistance between amorphous phase and crystalline phase. People can use these differences to store data. Not storing electric charge makes the minimization possible. Meanwhile, the speeds in which the storing materials change their phases can make growth of the reading and writing speeds likely. The high resistance characteristic of materials under amorphous phase greatly lowers the energy consumptions while reading data. These series of advantages are attracting people to do creative researches on the field of phase change Storage Technology. People found that there are some characteristics in chalcogenide materials, which makes them fits for making materials of phase change memory. Thus, people discovered many materials in chalcogenide materials, which are considered to become the momery of next generation potentially.1) We fabricate a series of Ti-doped Sb2Te films by magnetron sputter system. The Ti doping was realized via the target-attachment method that an appropriate amount of Ti foils were placed on the Sb2Te target during deposition. According to the EDS analysis, the Sb2Te, Ti0.16Sb2Te, Ti0.27Sb2Te and Ti0.64Sb2Te films are achieved by magnetron sputtering. According to the measurement, the crystallization temperatures for Sb2Te, Ti0.16Sb2Te, Ti0.27Sb2Te and Ti0.64Sb2Te are 140 ℃,153 ℃,159 ℃,174 ℃, respectively. The activation energy (Ea) of crystallization are1.90 eV,2.80 eV,2.97 eV,4.01 eV, respectively. In summary, Ti doped Sb2Te phase-change films were proposed. The crystallization characteristics and thermal properties are improved obviously. Doping Sb2Te with Ti element can lead to better amorphous thermal stability and higher crystallization temperature.2) We fabricate a series of GeTe4 and metal doped-GeTe4 films by RF magnetron sputter system. The impurity elements are Cu, Al and Ti, respectively. The metal doping was realized via the target-attachment method that an appropriate amount of metal foils were placed on the GeTe4 target during deposition. According to the EDS analysis, the components of these films are GeTe4, Cu0.52GeTe4, Cu0.81GeTe4, Cu1.37GeTe4, Al0.19GeTe4, Al0.33GeTe4, Al0.64GeTe4, Ti0.03GeTe4. The crystallization temperatures for these films are 260 ℃,241 ℃,234 ℃,225 ℃,256 ℃,257 ℃, 240 ℃,295 ℃, respectively. In summary, Cu and Al doped GeTe4 films were proposed. The crystallization characteristics and thermal properties are not improved. But doping GeTe4 with Ti element can lead to better amorphous thermal stability.