利用擴散摻雜改善鋯酸鍶薄膜記憶體之電阻轉態特性研究

Abstract

本論文以濺鍍法及溶膠法製備鋯酸鍶(SrZrO3)電阻轉換薄膜。在二氧化矽(200奈米)矽基板上鍍製白金下電極(80奈米)，接著沉積厚度為100奈米之鎳酸鑭(LaNiO3)為緩衝層，接著鍍上鋯酸鍶電阻薄膜，並在鋯酸鍶層內嵌入一金屬層，再接完成最後300奈米厚之鋁上電極，即為六層薄膜結構(Al/SrZrO3/Metal/SrZrO3/LaNiO3/Pt) 。隨後經由快速熱退火處理使金屬離子擴散至鋯酸鍶層內部，利用擴散摻雜增加其電阻轉態特性，以改善元件兩記憶狀態不穩定之問題，並探討在不同的金屬層擴散對於此結構的電阻轉態特性影響。此外我們也將探討元件的記憶體特性，並比較及探討不同金屬摻雜對記憶體特性的影響，更進一步由實驗結果來探討可能的電阻式記憶體的電阻轉換及傳導機制。

Recently various, next-generation nonvolatile memory were introduced and among those we focus our study on resistance random access memory (RRAM). The RRAM has bistable resistive switching characteristic which can exhibit two states of different resistance for logic level. Therefore, RRAM can be next-generation memory by this characteristic. Beside, RRAM has excellent characteristics of high-speed operation, low-power, simple structure and high-density integration. In this experiment, an 80-nm-thick Pt bottom electrode was deposited on SiO2/Si substrate, and follow by a 100-nm-thick LaNiO3 buffer layer and the SrZrO3 thin films were fabricated by sputtering and sol-gel methods. We deposite different metals into SZO thin films and finally, the 300-nm-thick Al top electrode were deposited to form the 6 layers structure Al/SrZrO3/Metal/SrZrO3/LaNiO3/Pt. Finally, we use rapid thermal annealing diffusion to dope the metal into SrZrO3 and it shows excellent electrical properties. Furthermore, the possible resistive switching mechanism based on our experimental results is also discussed in this thesis.