元素掺杂GST相变存储薄膜的热传导性能与机理研究

In phase change random access memory (PRAM), the transformation of phase change materials between amorphous and crystalline states is controlled by Joule-heating to record data. The thermal conductivity of phase change materials plays a key role in further reducing the volume and energy consuming of PRAM. However, the thermal conductivity of doped-Ge2Sb2Te5 (GST) phase change film is still not clearly understood although doped-GST has been proved to possess better application properties than GST film. Therefore, this project will measure the thermal conductivity of doped-GST film by 3w method. By comparing the thermal conductivity results of N-doped GST and Sn-doped GST films, this project will clarify the influence of metallic and non-metallic doping elements for the thermal conductivity of GST film as well as the influence of doping quantity. By combining the results of thermal conductivity and electrical resistivity measurements, the thermal conduction mechanism of doped-GST film will be discussed and a thermal conduction model will be constructed composed of free electron conduction, phonon conduction and other possible conduction ways. This model will provide a basis for predicting the thermal conductivity of other elements doped-GST films. The thermal conduction mechanism of doped-GST film will be clarified in this project, which is not only able to provide the key parameter for understanding the material structure and properties of GST itself, but also able to provide the relevant scientific foundation for the material selection and structure design in PRAM application.

相变存储器（PRAM）通过焦耳热使相变材料在非晶态和晶态间转变，从而实现数据存储。因而相变材料的热传导性是决定PRAM体积及能耗能否减小的关键因素。本项目基于元素掺杂能提高Ge2Sb2Te5（GST）相变薄膜的某些存储性能的研究背景，针对其热传导性能和机理仍不明了的现状，采用3w法对掺杂GST薄膜进行热传导测量。通过对非金属N和金属Sn两种元素掺杂GST薄膜热传导结果的对比，阐明不同性质的元素掺杂对于热传导性能的影响规律，同时揭示出掺杂量对热传导的影响；并结合电传导性能的测量，讨论不同元素掺杂的热传导机理，建立一个由电子、声子及其他可能存在的传导方式组成的热传导模型，为预测其他元素掺杂GST的热传导性能提供方法和指导。本研究可解决目前掺杂GST薄膜热传导机理不明的关键科学问题，不仅为今后GST材料结构和性质的研究提供关键参数，并能为PRAM应用中的材料选择和器件结构设计提供相关科学依据。

相变存储器（PRAM）通过焦耳热使相变材料在非晶态和晶态间转变，从而实现数据存储。因而相变材料的热传导性是决定PRAM体积及能耗能否减小的关键因素。本项目基于元素掺杂能提高Ge2Sb2Te5（GST）相变薄膜的某些存储性能的研究背景，针对其热传导性能和机理仍不明了的现状，采用3w法对掺杂GST薄膜进行热传导测量。本项目主要研究内容为1）3法结构设计研究；2）元素掺杂GST 薄膜制备的研究；3）元素掺杂GST 薄膜传导机理的研究。本项目成功确立了测量薄膜热传导的3w方法，为今后热电材料的研究打下基础。通过对非金属N和金属Sn两种元素掺杂GST薄膜热传导结果的对比，阐明不同性质的元素掺杂对于热传导性能的影响规律，同时揭示出掺杂量对热传导的影响；并结合电传导性能的测量，讨论不同元素掺杂的热传导机理，建立一个由电子、声子及其他可能存在的传导方式组成的热传导模型，为预测其他元素掺杂GST的热传导性能提供方法和指导。本研究解决了目前掺杂GST薄膜热传导机理不明的关键科学问题，不仅为今后GST材料结构和性质的研究提供关键参数，并能为PRAM应用中的材料选择和器件结构设计提供相关科学依据。