本文關(guān)鍵詞：碳納米管電極基阻變存儲(chǔ)器的特性研究　出處：《天津理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 阻變存儲(chǔ)器 碳納米管 氧化鉿 高密度

【摘要】：近年來,具有高密度、高速度和低功耗等特點(diǎn)的非揮發(fā)性存儲(chǔ)器件在存儲(chǔ)器的發(fā)展過程當(dāng)中占據(jù)著越來越重要的地位。而在眾多的新型非揮發(fā)性存儲(chǔ)器中,阻變存儲(chǔ)器展現(xiàn)出優(yōu)越的微型化潛能、較快的工作速率、較低的能量功耗及較高的擦寫次數(shù)等優(yōu)勢(shì),故其被認(rèn)為是取代傳統(tǒng)存儲(chǔ)器的最有利競(jìng)爭(zhēng)者之一。隨著器件的特征尺寸逐漸減小,碳納米管優(yōu)越的電學(xué)、熱學(xué)性能及納米量級(jí)的尺寸對(duì)于解決阻變存儲(chǔ)器尺寸限制提供了途徑。因此本文主要對(duì)碳納米管電極在阻變存儲(chǔ)器件中應(yīng)用進(jìn)行了探索,具體內(nèi)容如下:本文通過熱CVD的方法,主要從襯底退火工藝、催化劑的選擇、CH4/H2流量比、生長(zhǎng)時(shí)間和生長(zhǎng)溫度等方面對(duì)碳納米管的橫向生長(zhǎng)工藝進(jìn)行了探索和優(yōu)化。通過實(shí)驗(yàn)結(jié)果得出當(dāng)退火環(huán)境為500sccm O_2,退火溫度為900℃、退火時(shí)間為8h時(shí),襯底的均方根粗糙度最小,最有利于CNTs的生長(zhǎng);當(dāng)催化劑為1 nm Ni,CH4:H2=500:60,生長(zhǎng)溫度為900℃,生長(zhǎng)時(shí)間為40min時(shí),橫向碳納米管的生長(zhǎng)質(zhì)量相對(duì)最高,最有利于充當(dāng)阻變存儲(chǔ)器件的電極材料。并在該工藝條件基礎(chǔ)上成功制備了HfO_2/CNTs結(jié)構(gòu)阻變存儲(chǔ)器件。基于HfO_2/CNTs結(jié)構(gòu)阻變存儲(chǔ)器件,主要研究了Ta、Ti、Cu和Al四種不同金屬上電極對(duì)HfO_2/CNTs結(jié)構(gòu)阻變器件性能的影響。通過對(duì)四種結(jié)構(gòu)器件I-V特性的研究,發(fā)現(xiàn)所有器件都為典型的雙極性阻變特性,并都具有自限流特性,其中Al/HfO_2/CNTs結(jié)構(gòu)器件具有最低的功耗(Ireset=130 nA)及相對(duì)最好的阻變性能(自限流、forming-free和低阻態(tài)非線性等)。這也表明Al/HfO_2/CNTs結(jié)構(gòu)器件在高密度存儲(chǔ)領(lǐng)域極具應(yīng)用潛力。在Al/HfO_2/CNTs結(jié)構(gòu)器件的基礎(chǔ)上,本文還對(duì)該結(jié)構(gòu)器件的阻變層HfO_2厚度及催化劑線條的進(jìn)行了優(yōu)化。此外,通過與Al/HfO_2/Ti結(jié)構(gòu)器件阻變性能的對(duì)比,發(fā)現(xiàn)碳納米管電極在器件的自限流、超低功耗和低阻態(tài)非線性等阻變特性中發(fā)揮著至關(guān)重要的作用。最后,對(duì)Al/HfO_2/CNTs結(jié)構(gòu)器件高低阻態(tài)的電流傳導(dǎo)機(jī)理及相關(guān)阻變機(jī)理進(jìn)行了探索,并得出器件的高低阻態(tài)分別遵循陷阱控制的空間電荷限制電流機(jī)制和空間電荷限制電流機(jī)制。因此器件的阻變機(jī)理可以歸結(jié)于HfO_2薄膜里的陷阱對(duì)電子的俘獲與釋放。通過對(duì)比研究,發(fā)現(xiàn)碳納米管電極在阻變過程中僅僅是充當(dāng)注入和釋放電子的載體,HfO_2在器件的阻變機(jī)理中發(fā)揮著關(guān)鍵性作用。Al/HfO_2/CNTs器件的物理阻變模型因此也被提出。
[Abstract]:In recent years, non-volatile memory devices with the characteristics of high density, high speed and low power consumption play an increasingly important role in the development of memory. Resistive memory has the advantages of superior miniaturization potential, faster working rate, lower energy consumption and higher erasing times. Therefore, it is considered to be one of the most favorable competitors to replace the traditional memory. As the characteristic size of the device gradually decreases, carbon nanotubes (CNTs) are superior in electricity. Thermal properties and nanoscale sizes provide a way to solve the resistive memory size limit. Therefore, the application of carbon nanotube electrodes in resistive memory devices is explored in this paper. The main contents are as follows: in this paper, by means of thermal CVD, the substrate annealing process, the selection of catalyst and Ch _ 4 / H _ 2 flow ratio are discussed. The transverse growth process of carbon nanotubes was investigated and optimized in terms of growth time and growth temperature. The experimental results showed that the annealing temperature was 900 鈩，

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