相變存儲(chǔ)單元多值存儲(chǔ)的仿真研究
發(fā)布時(shí)間：2019-04-09 20:56
【摘要】：隨著智能移動(dòng)終端的崛起，消費(fèi)市場(chǎng)需要集成度高、速度快、容量大的存儲(chǔ)芯片。以Flash為代表的傳統(tǒng)固態(tài)存儲(chǔ)芯片逐漸面對(duì)微縮工藝降低可靠性等方面的問(wèn)題。因此，新型存儲(chǔ)器日益成為研發(fā)焦點(diǎn)，其中相變隨機(jī)存儲(chǔ)器以其讀寫(xiě)速度快、讀寫(xiě)次數(shù)高、微縮特性好、數(shù)據(jù)保存時(shí)間長(zhǎng)等優(yōu)勢(shì)而成為下一代主流存儲(chǔ)器技術(shù)之一。 本文主要研究相變隨機(jī)存儲(chǔ)器存儲(chǔ)單元的多值存儲(chǔ)機(jī)理,研究了多值存儲(chǔ)過(guò)程中器件物理性質(zhì)及相變過(guò)程，并對(duì)其進(jìn)行量化及仿真計(jì)算。根據(jù)有限元法，仿真系統(tǒng)將主方程與材料參數(shù)結(jié)合，建立仿真模型，編制了仿真計(jì)算程序�；诜�、脈寬以及連續(xù)脈沖的電脈沖控制存儲(chǔ)單元和存儲(chǔ)單元總電阻判斷存儲(chǔ)效果的研究思路，對(duì)單個(gè)存儲(chǔ)單元的多值存儲(chǔ)控制方法、多值存儲(chǔ)過(guò)程、制程變差的影響以及數(shù)據(jù)保存時(shí)間方面進(jìn)行了較全面的多值分析，研究了單元內(nèi)部相變層相態(tài)分布及溫度變化趨勢(shì)，制程變差影響與相變材料自發(fā)晶化影響下的多值存儲(chǔ)狀態(tài)穩(wěn)定性。 仿真實(shí)驗(yàn)結(jié)果表明，相變存儲(chǔ)單元可通過(guò)單電脈沖控制幅值、脈寬的方式或連續(xù)脈沖控制脈沖數(shù)的方式實(shí)現(xiàn)四值存儲(chǔ)，四種存儲(chǔ)狀態(tài)分別處于1kΩ、10k Ω、100kΩ及1M Ω數(shù)量級(jí)上。相態(tài)分析表明，存儲(chǔ)單元總電阻與相變層與底電極接觸附近區(qū)域的相態(tài)分布緊密相關(guān)，，當(dāng)非晶相態(tài)覆蓋住該區(qū)域時(shí)存儲(chǔ)單元電阻大幅上升，反之則迅速下降。多值存儲(chǔ)狀態(tài)穩(wěn)定性分析表明，存儲(chǔ)過(guò)程對(duì)存儲(chǔ)單元內(nèi)部尺寸變化的敏感性不一，其中相變層厚度變化對(duì)存儲(chǔ)狀態(tài)影響較大，以致存儲(chǔ)狀態(tài)電阻分布可能出現(xiàn)交疊；在80℃的環(huán)境下，存儲(chǔ)單元信息可保持10年以上且不失效。
[Abstract]:With the rise of intelligent mobile terminals, the consumer market needs memory chips with high integration, high speed and large capacity. The traditional solid-state memory chips represented by Flash are gradually faced with the problems of reducing the reliability of microscale technology. Therefore, new memory has become the focus of research and development day by day, in which phase transition random access memory has become one of the next generation mainstream memory technology because of its advantages such as high speed of reading and writing, high times of reading and writing, good characteristic of miniaturization, long data storage time, and so on. In this paper, we mainly study the multi-valued storage mechanism of the phase transition random memory cell, and study the physical properties and phase transition process of the device in the multi-valued storage process, and carry on the quantification and the simulation calculation to it. According to the finite element method, the simulation system combines the master equation with the material parameters, establishes the simulation model, and compiles the simulation calculation program. Based on amplitude, pulse width and continuous pulse, the memory cell and the total resistance of the storage unit are used to judge the storage effect. The multi-valued storage control method and the multi-valued stored procedure for a single memory cell are presented. In this paper, the influence of process variation and the time of data preservation are analyzed comprehensively, and the phase distribution and temperature change trend of phase transition layer in the cell are studied. The effect of process variation on the stability of multi-valued storage state under the influence of spontaneous crystallization of phase change materials. The simulation results show that the phase change storage cell can realize four-valued storage by means of controlling amplitude, pulse width or continuous pulse number by single electric pulse, and the four storage states are in the order of 1k 惟, 10k 惟, 100k 惟 and 1m 惟, respectively, in the order of magnitude of 1k 惟, 10k 惟, 100k 惟 and 1m 惟 respectively. The phase analysis shows that the total resistance of the storage cell is closely related to the distribution of the phase state near the contact area between the phase transition layer and the bottom electrode. When the amorphous phase state covers the region, the resistance of the memory cell increases significantly, whereas the resistance of the memory cell decreases rapidly. The stability analysis of multi-valued storage state shows that the sensitivity of stored procedure to the change of internal size of storage cell is different, and the change of phase transition layer thickness has a great influence on the storage state, so that the resistance distribution of storage state may overlap. At 80 鈩
本文編號(hào)：2455528
[Abstract]:With the rise of intelligent mobile terminals, the consumer market needs memory chips with high integration, high speed and large capacity. The traditional solid-state memory chips represented by Flash are gradually faced with the problems of reducing the reliability of microscale technology. Therefore, new memory has become the focus of research and development day by day, in which phase transition random access memory has become one of the next generation mainstream memory technology because of its advantages such as high speed of reading and writing, high times of reading and writing, good characteristic of miniaturization, long data storage time, and so on. In this paper, we mainly study the multi-valued storage mechanism of the phase transition random memory cell, and study the physical properties and phase transition process of the device in the multi-valued storage process, and carry on the quantification and the simulation calculation to it. According to the finite element method, the simulation system combines the master equation with the material parameters, establishes the simulation model, and compiles the simulation calculation program. Based on amplitude, pulse width and continuous pulse, the memory cell and the total resistance of the storage unit are used to judge the storage effect. The multi-valued storage control method and the multi-valued stored procedure for a single memory cell are presented. In this paper, the influence of process variation and the time of data preservation are analyzed comprehensively, and the phase distribution and temperature change trend of phase transition layer in the cell are studied. The effect of process variation on the stability of multi-valued storage state under the influence of spontaneous crystallization of phase change materials. The simulation results show that the phase change storage cell can realize four-valued storage by means of controlling amplitude, pulse width or continuous pulse number by single electric pulse, and the four storage states are in the order of 1k 惟, 10k 惟, 100k 惟 and 1m 惟, respectively, in the order of magnitude of 1k 惟, 10k 惟, 100k 惟 and 1m 惟 respectively. The phase analysis shows that the total resistance of the storage cell is closely related to the distribution of the phase state near the contact area between the phase transition layer and the bottom electrode. When the amorphous phase state covers the region, the resistance of the memory cell increases significantly, whereas the resistance of the memory cell decreases rapidly. The stability analysis of multi-valued storage state shows that the sensitivity of stored procedure to the change of internal size of storage cell is different, and the change of phase transition layer thickness has a great influence on the storage state, so that the resistance distribution of storage state may overlap. At 80 鈩
本文編號(hào)：2455528
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