面向相变存储器测试的精密电流源设计

发布时间：2018-01-12 23:20

本文关键词：面向相变存储器测试的精密电流源设计　出处：《华中科技大学》2012年硕士论文　论文类型：学位论文

【摘要】：相变存储器是以相变材料为存储介质的新型非易失性半导体存储器，它利用电脉冲产生的焦耳热使相变材料产生较大阻值差异的可逆相变实现信息存储，因此脉冲电流源是相变存储器实现信息存储的关键器件，本文采用两种方案对用于相变存储器测试的精密脉冲电流源进行研究设计。本文根据相变存储器的工作原理以及其对测试用脉冲电流源的要求，采用模块化设计思想，利用现有集成度高的成熟芯片设计了用于相变存储器测试的超宽带精密电流源。纳秒级窄脉冲产生电路采用数字电路方法，利用CPLD芯片作为脉冲产生电路的逻辑控制单元，在精密可编程延迟芯片DS1020的作用下产生脉冲宽度步进可调的纳秒级窄脉冲,脉冲幅值控制电路是由D/A转换芯片产生的模拟电压控制，最后电流驱动部分采用激光二极管驱动芯片EL6257实现，脉冲电流的幅值和宽度可以通过上位机设置。本文针对相变存储器高速低功耗测试的需要，，对一种基于MOS管的低功耗精密电流镜进行了研究分析，并利用Pspice仿真软件，建立仿真模型，基于TSMC0.18μmCMOS，BSIM3，Level49工艺对此电流镜的性能进行仿真验证，仿真结果表明此电路输出电流精确度高稳定性好，并且可以达到很宽的带宽，适合用作相变存储器测试的激励脉冲源。同时本文针对脉冲电流源的具体应用，介绍了相变存储单元瞬态电流的测量方法，并根据测量电路等效电路模型分析影响测量的因素，最终实现了相变存储单元瞬态电流，R-I特性曲线的精确测量。研究结果表明，本论文研究设计的精密电流源在脉冲宽度和脉冲幅值上可精确可调，为相变存储器的测试奠定了基础。
[Abstract]:Phase change memory (PCM) is a new type of nonvolatile semiconductor memory with phase change material as the storage medium. It uses the Joule heat produced by electric pulse to make phase change material produce large difference in resistance value to realize the information storage. Therefore, pulse current source is the key device of phase change memory to realize information storage. In this paper, two schemes are adopted to study and design the precise pulse current source used for phase change memory testing. According to the working principle of phase change memory and the requirement of pulse current source for testing, the modular design idea is adopted in this paper. An ultra-wideband precise current source for phase change memory testing is designed by using existing mature chips with high integration. The nanosecond narrow pulse generation circuit adopts digital circuit method. Using the CPLD chip as the logic control unit of the pulse generation circuit, the pulse width step adjustable nanosecond narrow pulse is generated under the action of the precision programmable delay chip DS1020. The pulse amplitude control circuit is controlled by analog voltage generated by D / A conversion chip, and the final current drive part is realized by laser diode driver chip EL6257. The amplitude and width of the pulse current can be set by the upper computer. In order to meet the need of high speed and low power test of phase change memory, a kind of low power precision current mirror based on MOS transistor is studied and analyzed in this paper, and the simulation model is established by using Pspice simulation software. The performance of the current mirror is verified by simulation based on TSMC0.18 渭 m CMOS / BSIM3 / Level49 process. The simulation results show that the output current accuracy of this circuit is high and stable. It can be used as an exciting pulse source for phase change memory testing because of its wide bandwidth. At the same time, according to the specific application of pulse current source, this paper introduces the measurement method of transient current in phase change memory cell, and analyzes the factors that affect the measurement according to the equivalent circuit model of measurement circuit. Finally, the accurate measurement of the transient current and R-I characteristic curve of the phase change memory cell is realized. The results show that the precision current source designed in this paper can be accurately adjustable in pulse width and pulse amplitude, which lays a foundation for the testing of phase change 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】：TN782

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