本文選題：阻變存儲器　切入點：非易失性　出處：《清華大學》2013年博士論文　論文類型：學位論文

【摘要】：阻變存儲器是下一代存儲器的有力競爭者之一，是一種同時具備高速和高密度存儲潛力的非易失性存儲器。尋找適合于阻變存儲器的介質(zhì)材料，，完善電阻轉(zhuǎn)變的物理機制，并制備性能優(yōu)異的阻變存儲器一直是半導體工業(yè)界和科學界關注的熱點之一。本文采用磁控濺射技術沉積了AlN、Ta2O5和ZnO薄膜，并制備了陽離子遷移型和陰離子遷移型兩類阻變存儲器器件，系統(tǒng)研究了存儲介質(zhì)厚度、器件尺寸、上電極材料、限流值、工作溫度等因素對阻變存儲器性能的影響，并結合對存儲介質(zhì)薄膜及其與電極界面的顯微結構和化學狀態(tài)的分析，重點澄清各項工藝參數(shù)對不同類型阻變存儲器的電阻轉(zhuǎn)變行為的影響，以期獲得高性能的阻變存儲器器件。 研究結果表明，AlN薄膜是一種性能優(yōu)良的阻變存儲器介質(zhì)材料，基于Ag或Cu離子遷移的(Ag，Cu)/AlN/Pt雙極性阻變器件的電阻轉(zhuǎn)變陡峭，高低阻態(tài)之間的窗口值超過103，數(shù)據(jù)保持時間超過106s。器件高低阻態(tài)的溫度特性證明了其電阻轉(zhuǎn)變基于Ag/Cu金屬導電細絲的形成和斷開。通過在AlN薄膜中引入彌散分布的Cu原子獲得了Pt/AlN:Cu/Pt單極性阻變存儲器，該器件響應速度高，能夠在100ns的短脈沖激勵下完成擦寫操作。而通過串聯(lián)反接兩個雙極性AlN阻變器件還成功構造了相應的互補型阻變存儲器，從而獲得了基于AlN薄膜的雙極性、單極性和互補型阻變存儲器，將阻變存儲器的選材范圍擴展到了氮化物體系。 基于Ta2O5薄膜的阻變存儲器中氧離子的遷移對于電阻轉(zhuǎn)變有重要作用，實驗利用X射線光電子能譜表征了W/Ta2O5/Pt器件分別處于高阻態(tài)和低阻態(tài)時W/Ta2O5界面與Ta2O5/Pt界面處Ta的化學價態(tài)的變化，表明了在正負電場作用下氧離子的遷移運動是器件發(fā)生電阻轉(zhuǎn)變的微觀機理。通過電極優(yōu)化工程，研究了不同化學活性的上電極材料對Ta2O5基阻變存儲器性能的影響，結果表明與Ta化學活性相近的Al，Ti，W等金屬做上電極時，器件的閾值電壓和高低電阻態(tài)的分布表現(xiàn)出較小的分散性，是Ta2O5基阻變存儲器上電極的最佳選擇。在優(yōu)化電極后的Ta2O5基阻變存儲器中成功觀察到了量子導電現(xiàn)象，證明了量子導電行為不依賴于導電細絲的種類，是原子級別導電細絲的一種本征現(xiàn)象。 實驗還獲得了具有自整流效應的Al/ZnO/Si阻變存儲器，驗證了電場作用下氧離子的遷移運動導致Al/ZnO界面處AlOx的變化是器件發(fā)生電阻轉(zhuǎn)變的物理機制。該器件0.5V時的存儲窗口值達到103，低阻態(tài)時在±0.5V的整流比超過102。
[Abstract]:Resistive memory is one of the most powerful contenders for next generation memory. It is a kind of nonvolatile memory with high speed and high density storage potential. The fabrication of high performance resistive memory has been one of the hot topics in semiconductor industry and scientific field. In this paper, AlNN- Ta _ 2O _ 5 and ZnO thin films were deposited by magnetron sputtering. Two kinds of impedance memory devices, cationic migration type and anionic migration type, are prepared. The effects of storage medium thickness, device size, material of upper electrode, current limiting value and working temperature on the performance of the impedance memory are systematically studied. Based on the analysis of the microstructure and chemical state of the film and its interface with the electrode, the influence of various process parameters on the resistance transition behavior of different types of resistive memory is clarified. In order to obtain high performance resistive memory devices. The results show that AlN thin film is an excellent dielectric material for resistive memory. The resistance transition of Ag-CuN / AlN / AlN / Pt bipolar impedance devices based on Ag or Cu ion migration is steep. The window value between the high and low resistance states is more than 103 and the data retention time is more than 106 s. The temperature characteristics of the high and low resistance state of the device prove that the resistance transition is based on the formation and disconnection of the Ag/Cu metal conductive filament. The dispersion distribution is introduced into the AlN thin film. The Pt/AlN:Cu/Pt unipolar resistive memory is obtained. The device has high response speed and can finish the writing operation under the excitation of 100ns short pulse. The corresponding complementary resistive memory is also constructed successfully by the series reverse connection of two bipolar AlN devices, thus the bipolar device based on AlN thin film is obtained. Monopole and complementary resistive memory extend the selection range of resistive memory to nitride system. The migration of oxygen ions in resistive memory based on Ta2O5 thin film plays an important role in resistance transition. The chemical valence states of Ta at the interface of W / Ta _ 2O _ 5 and Ta2O5/Pt were characterized by X-ray photoelectron spectroscopy (XPS) when the W / Ta _ 2O _ 5 / Pt devices were in high resistance state and low resistance state, respectively. It is shown that the migration of oxygen ions under positive and negative electric field is the microcosmic mechanism of the resistance transition of the device. The influence of the materials with different chemical activity on the performance of Ta2O5 based impedance memory is studied by electrode optimization engineering. The results show that the distribution of the threshold voltage and the high and low resistance states of the device shows a small dispersion when the metal such as Al _ (Ti) Ti _ W is used as the upper electrode, which is similar to Ta's chemical activity. It is the best choice of electrode in Ta2O5 basic impedance memory. Quantum conduction phenomenon has been observed successfully in Ta2O5 base impedance memory after optimized electrode. It is proved that the quantum conduction behavior is independent of the type of conductive filament. It is an intrinsic phenomenon of conducting filament at atomic level. The Al/ZnO/Si resistive memory with self-rectifying effect is also obtained. It is proved that the change of AlOx at the interface of Al/ZnO due to the migration of oxygen ions under the action of electric field is the physical mechanism of resistance transition of the device. The storage window value of the device reaches 103 at 0.5 V and the rectifier ratio of 鹵0.5V at 鹵0.5 V in the low resistance state is more than 102.
【學位授予單位】：清華大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TB383.2;TP333

【參考文獻】

相關期刊論文 前1條

1 ;Giant piezoresponse and promising application of environmental friendly small-ion-doped ZnO[J];Science China(Technological Sciences);2012年02期

本文編號：1636520