SiN_x掺杂SbTe相变存储材料研究

发布时间：2018-06-24 07:23

本文选题：相变存储器 + SiNx掺杂SbTe　；参考：《上海交通大学》2012年硕士论文

【摘要】：近几年来随着消费电子市场的快速增长,存储器的市场越来越大,目前应用最广泛的不挥发存储器是基于浮栅技术的闪存。然而,由于其自身物理机制上的限制,闪存单元尺寸的进一步缩小遇到了很多的技术瓶颈。相变存储器(Phase Change Random Access Memory,简称PRAM)因为具有存储单元尺寸小、非挥发性、循环寿命长、功耗低、读/写速度快以及和现有的CMOS工艺兼容等优点,被认为是最有可能取代闪存成为未来可通用的新一代存储器技术。当前,在PRAM中广泛采用的相变材料是Ge-Sb-Te(GST)薄膜,但其存在一些需要改善的问题,如RESET电流较大,高温下的数据保存寿命有待提高等问题,难以满足未来不挥发存储器对低功耗,数据稳定性等的要求。对此,人们研究了在Sb_2Te_3中掺杂Si元素从而形成的SST材料。SST材料具有更好的非晶态热稳定性,更高的晶态电阻率以及更低的熔化温度,然而在结晶过程中会分离出Te晶相是SST材料的一个很大的问题,会对器件的稳定性造成一定的影响。为了既能保留SST材料的优势,又要减弱Te晶相的产生,本论文尝试对Sb2Te3中掺杂SiNx,主要进行了以下的研究: 1.制备不同浓度SiNx掺杂SbTe薄膜。利用XRD、TEM和原位恒温退火等实验研究薄膜成分、结构特性和电学性能。XRD和TEM结果表明,结晶后主要是Sb2Te3晶相,分布在SiNx材料中形成为一种纳米复合材料,高电阻的SiNx可以作为微加热器,并且此结构能够提高晶态电阻率,从而有利于降低器件的RESET电流。原位恒温退火实验结果表明,随着SiNx浓度的增加,SiNx-SbTe材料的晶化温度升高,非晶态和晶态电阻率提高,数据保存能力大大提高。 2.制备基于SiNx-SbTe材料的相变存储器件原型,研究其电学性能和转变机理。该器件具有记忆开关特性,并且能够实现SET和RESET操作。测试结果表明,基于5at.% SiNx-SbTe材料制备的器件具有记忆开关特性,可以在大小、脉冲宽度、下降沿宽度分别为2.2V-80ns-50ns的脉冲下实现SET操作,在4.2V-20ns-5ns的脉冲下实现RESET操作。
[Abstract]:In recent years, with the rapid growth of consumer electronics market, the market of memory is becoming larger and larger. At present, the most widely used non-volatile memory is flash memory based on floating gate technology. However, due to the limitations of its own physical mechanism, the further reduction of flash memory unit size encountered a lot of technical bottlenecks. Phase change Random Access memory (pram) has the advantages of small memory cell size, non-volatile, long cycle life, low power consumption, fast read / write speed and compatibility with existing CMOS processes. It is considered most likely to replace flash memory as a new generation of memory technology that can be used in the future. At present, the phase change material widely used in pram is Ge-Sb-Te (GST) thin film, but there are some problems that need to be improved, such as large RESET current, high temperature data storage life and so on, so it is difficult to meet the low power consumption of non-volatile memory in the future. Requirements for data stability, etc. In this regard, it has been studied that the SST material SST formed by doping Si in SbStu2Te3 has better amorphous thermal stability, higher crystalline resistivity and lower melting temperature. However, the separation of Te phase in the crystallization process is a major problem for SST materials, which will have a certain impact on the stability of the device. In order to preserve the advantages of SST materials and weaken the generation of Te crystal phase, the following researches have been done in this thesis: 1. In this thesis, the doping of SiNx in SB _ 2TE _ 3 is studied as follows: 1. SiNx doped SbTe thin films with different concentrations were prepared. The composition, structure and electrical properties of the films were investigated by XRDX TEM and in-situ isothermal annealing. XRD and TEM results showed that the crystalline phase was mainly Sb2Te3, which was distributed in Sinx material to form a kind of nanocomposite. The SiNx with high resistance can be used as a micro-heater, and the structure can increase the resistivity of the crystal state, thus reducing the RESET current of the device. The in-situ isothermal annealing results show that with the increase of Sinx concentration, the crystallization temperature of SiNx-SbTe increases, the resistivity of amorphous and crystalline states increases, and the data storage ability is greatly improved. 2. A phase change memory device prototype based on SiNx-SbTe was prepared and its electrical properties and transition mechanism were studied. The device has the characteristics of memory switch and can realize set and reset operation. The test results show that the device based on 5at.% SiNx-SbTe has memory switching characteristics, and can realize set operation at pulse size, pulse width and descent edge width of 2.2V-80ns-50ns, and RESET operation under 4.2V-20ns-5ns pulse.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP333

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