- 學位論文
銦電極於氧化鉿電阻式記憶體之電性機制研究
Study on Indium Electrode Effect of Hafnium oxide-based Resistance Random Access Memory(RRAM)
摘要
本論文研究重點在發現引入銦(Indium)金屬作為電極，並以半導體工業常見之氧化鉿材料作為絕緣切換層之電阻式記憶體(RRAM)元件。實驗結果顯示此In/HfO2/TiN元件具有相當優異的性能，包括高判讀窗口、低操作電壓、低功耗與高切換速度等優點。 此外，本實驗透過半導體精準電性儀Agilent B1500A與快速電性量測技術(Fast-IV)解析電阻式記憶元件的物理傳導機制；並輔以穿透式電子顯微鏡觀察到銦元素在絕緣層中擴散之現象。 不僅如此，我們發現此In/HfO2/TiN元件在給予較高的SET限制電流時，元件的高阻態電阻值卻隨之下降現象，此特性與常見之白金/氮化鈦做為電極之氧化鉿電阻式記憶體有諸多差異。藉由詳細的電性量測結果，我們推測是元件內形成的阻絲變粗，且銦鉿氧化層變厚造成RESET結果較差。而藉由快速量測，我們發現此元件在低電阻態轉變為高電阻態的切換過程傳導機制皆屬於蕭特基傳導(Schottky)，此外隨操作電壓上升時，蕭特基斜率及截距皆下降，直到元件內部產生劇烈RESET反應。
並列摘要
In this study, indium metal was introduced as the electrode with HfO2-based of RRAM device. The device is fabricated as the structure of In/HfO2/TiN which produce characteristics of low operation voltage, low power consumption, high read margin order and high switching speed. The Agilent B1500A semiconductor analyzer and fast current-voltage (fast-IV) instrument are applied to investigate the resistance switching (RS) characteristics of this device. With the observation of transmission electron microscope (TEM) results, the indium electrode is found to diffuse into the dielectric layer. Not only that, the HRS of In/HfO2/TiN device decreases with increasing SET current compliance, this phenomenon is unlike the RRAM with platinum as electrode, which suggests poorer RESET quality was found due to the formation of thicker filament and InHfOx oxidized layer. Moreover, before the appearance of severe RESET behavior, the Schottky slope and intercept all decrease with increasing operating voltages according to the fast-IV results. This result has indicated that an oxidized layer is produced between top indium and middle insulator to affect the RS characteristics of this device.