非对称相变存储器单元制备工艺及性能研究

发布时间：2018-03-29 08:39

本文选题：相变存储器　切入点：五层非对称结构存储单元　出处：《华中科技大学》2012年硕士论文

【摘要】：相变存储器PCRAM(phase change random access memory)是一种以硫系化合物为存储介质的随机存储器。其利用电能使材料在晶态和非晶态之间相互变换实现数据的写入与擦除。相比现存的其他类型存储器，相变存储器具有非易失性、循环寿命长、元件尺寸小、功耗低、多级存储特点，在数据读写速度可擦写次数读取方式工作电压以及工艺兼容性等各项性能指标上有着独特的优势。基于其各方面优势，相变存储器被认为是下一代存储器的主流产品。 PCRAM的研究过程中遇到的最大问题便是操作电流过大。为了改善写信息脉冲电流过高制约相变随机存储器实用化的状况，，本文在运用有限元分析软件ANSYS模拟计算和对比了传统T型结构和非对称结构的热学性能和电学性能之后，得到非对称结构的写电流要优于前者的结论。在此基础上本文设计相变存储器五层非对称结构的基本单元，运用光刻、溅射以及剥离等工艺实现了器件单元的制备。测试结果表明，采用光刻、溅射以及剥离等工艺制备的相变存储器五层非对称结构单元导通且能反复擦写，I-V特性曲线表明发生了相变，很好的满足了相变存储器的重要性能参数。另外，分别对单元的第二层、第三层膜厚和非对称位移量对单元写电流的性能影响进行研究，得到相对有利于降低存储器写电流的非对称结构。
[Abstract]:Phase change memory (PCRAM(phase change random access memory) is a random access memory in which sulfur compounds are used as storage media. It uses electrical energy to transform materials between crystalline and amorphous states to write and erase data. Phase change memory has the characteristics of non-volatile, long cycle life, small element size, low power consumption, multilevel storage, and high speed in data reading and writing. Erasable number of times? How to read? Because of its advantages, phase change memory is considered as the main product of next generation memory. The biggest problem encountered in the research of PCRAM is that the operating current is too large. In order to improve the condition that the pulse current of writing information is too high to restrict the application of phase-change random access memory, In this paper, the thermal and electrical properties of traditional T-type structures and asymmetric structures are simulated and compared by using finite element analysis software ANSYS. Based on the conclusion that the write current of asymmetric structure is superior to that of the former, the basic elements of phase change memory (PCM) five-layer asymmetric structure are designed in this paper. The fabrication of device cells is realized by photolithography, sputtering and stripping techniques. The experimental results show that the phase change memory (PCM), which is fabricated by photolithography, sputtering and peeling, can be switched on and can repeatedly erase the I-V characteristic curve of phase change memory. In addition, the effects of the second layer, the third layer thickness and the asymmetric displacement on the performance of the cell write current are studied. An asymmetric structure is obtained which is relatively conducive to reducing the write current of the memory.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP333

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