二氧化鈰及氧化鋅組成雙層穿透性電阻式記憶體之研究

Abstract

近期有關於電阻式轉態元件在非揮發性記憶體的領域上吸引到了許多的注意，而電阻式隨機存取記憶體有以下許多的優勢，如:高存取速度、高密度、小尺寸、低功率及結構簡單。 在本論文中，有關於非揮發性記憶體中具透明特性之電阻式記憶體會被討論。此透明式電阻式記憶體擁有雙重存取組態的特性，可藉由雙重存取組態作為邏輯辨認。相較於傳統的記憶體元件，此類記憶體具有較高速度、較低的功率及高度的整合密度使得其可能成為下個世代的主要記憶體。而其製作過程和傳統CMOS製程具相容性，其基礎為金屬-絕緣體-金屬的簡易結構(在本文中為雙層絕緣體結構)且可在低溫製程中完成。 此類透明式記憶體元件是建立在，具有銦錫氧化物的玻璃基板上。首先利用濺鍍系統沉積氧化鋅，接著使用相同的系統沉積氧化鈰，最後則沉積銦錫氧化物 作為上端電極。本文中，探討使用銦錫氧化物作為上端電極所引發的元件特性，並且對於物理機制、電性、可靠度做全面性的分析。有關元件的傳導及轉態機制也將會做討論。最後，藉由本論文的研究總結可以突顯出此元件在未來記憶體應用上的潛力。

In recent times the concept of resistance based switching devices have drawn considerable amount of attention as the next non-volatile memory. The advantages it of Resistive Random Access memory is believed to be on fast operation, high density, small size , low power consumption and simple structure. In the present research work, we have studied the non-volatile memory characteristics of Transparent resistive random access memory (RRAM) devices, which have been fabricated and tested in the laboratory The Transparent RRAM has bi-stable switching characteristics, which exhibit two states of different resistances for logic levels. Compared to conventional memory devices, it has higher speed, lower power requirements and higher integration density making it potentially attractive for next-generation memory systems. The fabrication process of the device is CMOS compatible, having a simple MIM structure (in our case its bilayer) and requiring low processing temperature. This transparent memory device has been fabricated on glass substrate coated with Indium Tin Oxide (ITO). RF magnetron sputtering has been used to deposit a layer of ZnO on it followed by a layer of CeO2 and finally top electrodes have been formed using ITO. We used the top electrodes namely ITO to check their role on the device characteristics. Thereafter, the physical, electrical and reliability characteristics of the devices have been studied in detail. The conduction and switching mechanisms of the devices have been investigated. Finally the summary of the research study highlighting the potential of the device for future applications and scope for further work is presented.