相变存储单元的仿真研究

发布时间：2018-03-28 14:45

本文选题：相变随机存储器　切入点：相变存储单元　出处：《华中科技大学》2013年硕士论文

【摘要】：闪存存储器作为当前主流非易失性存储器，被广泛应用于各种场合，然而闪存存储器的发展受到其自身存储机理的限制，在后续几代工艺中将面临更大的挑战，亟待开发新型存储器以满足存储市场日益增长的需求。基于硫属化合物的相变随机存储器被认为最有希望取代闪存存储器成为下一代主流非易失性存储器。本文基于相变随机存储器的存储机理，通过建立存储单元仿真系统，对相变存储单元进行仿真研究，研究涉及单元几何参数、物理参数对存储单元工作电压、操作速度的影响以及存储单元的抗单粒子辐照性能。首先，基于拉普拉斯方程、傅里叶热传导方程、经典成核/生长理论、Thermal Spike模型建立存储单元仿真系统；其次，，在仿真系统的基础上通过改变存储单元几何参数、物理参数研究其对存储单元工作电压、操作速度的影响并在研究结果的基础上进行存储单元优化设计；最后，通过改变单个外界辐照粒子的能量，研究静态存储单元抗单粒子辐照性能。文中研究的几何参数包括：上下电极三维尺寸，相变层三维尺寸；研究的物理参数包括：上下电极材料的电阻率、热导率，相变材料的电阻率、热导率，绝缘介质所用材料。研究结果表明，相变层Z方向尺寸、相变材料电阻率、绝缘介质材料类型对存储单元性能影响较大；减小相变层Z方向尺寸、相变材料电阻率，使用合适的绝缘介质材料有助于减小单元操作电压、提高单元操作速度；在仿真粒子能量范围内，由辐照粒子引起的存储单元总电阻最大增加比例为1%，被辐照后存储单元能进行正常的读写操作，相变存储单元在未来几代工艺中仍有较好的抗单粒子辐照性能。
[Abstract]:Flash memory, as the current mainstream non-volatile memory, has been widely used in various occasions. However, the development of flash memory is limited by its own storage mechanism, which will face more challenges in the next few generations of technology. It is urgent to develop new memory to meet the increasing demand of storage market. Phase change random access memory based on sulfur compounds is considered as the most promising alternative to flash memory as the next generation of non-volatile memory. Based on the storage mechanism of phase change random access memory (PCRAM), a memory cell simulation system is established in this paper, which involves the geometric parameters of the cell, the working voltage of the memory cell and the physical parameters. The effect of operation speed and the radiation resistance of memory cell to single particle. Firstly, based on Laplace equation, Fourier heat conduction equation, classical nucleation / growth theory and thermal Spike model, the memory cell simulation system is established. The effects of physical parameters on the working voltage and operating speed of the memory cell are studied and the optimal design of the memory cell is carried out on the basis of the results. Finally, by changing the energy of a single external irradiated particle, In this paper, the geometric parameters of the static memory cell are studied, including the three-dimensional size of the upper and lower electrode, the three-dimensional dimension of the phase transition layer, the physical parameters including the resistivity of the upper and lower electrode materials, the thermal conductivity of the upper and lower electrode materials, the thermal conductivity of the upper and lower electrode materials. The resistivity, thermal conductivity, and insulating materials of phase change materials. The results show that the size of phase change layer Z direction, the resistivity of phase change material and the type of insulating dielectric material have great influence on the performance of the storage cell, and the resistivity of phase change material can be reduced by decreasing the Z direction size of phase change layer. The use of suitable insulating dielectric materials can reduce the operating voltage of the unit and increase the operating speed of the unit; in the range of simulated particle energy, The maximum increase ratio of the total resistance of the memory cells caused by irradiated particles is 1. The memory cells after irradiation can perform normal reading and writing operations. The phase change memory cells still have better resistance to single particle irradiation in the next few generations.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333

【共引文献】