| 摘要: | 隨著物聯網、人工智慧、自動駕駛等領域的迅速發展，對於存儲技術的需求也將不斷增加。在這些新興記憶體技術中，非揮發性記憶體（Non-Volatile Memory，NVM）扮演著越來越重要的角色。NVM的主要特色是在斷電後能夠長時間保持原本的儲存狀態，同時需具備良好的可擴張性、高速、低功耗、較長的壽命以及耐久性。
這使得NVM成為未來數據存儲和處理中不可或缺的一部分。
在本次實驗中，我們專注於非揮發性記憶體中常見的鐵電記憶體，特別是鐵電電容記憶體（FeCAP）和鐵電場效應電晶體（FeFET）這兩種元件。我們從製程技術出發，詳細記錄了製程過程，並從材料分析和電性量測兩個角度對其進行了評估和比較。最終，我們提出了一種利用氫電漿修復介面處捕捉電荷的方法，並有效地減少了在低溫薄膜沉積時產生非預期的碳元素。這一方法提升了元件的穩定性、操作速度和可靠性。
在這項實驗中，我們探討了氫電漿對以鋯鈰氧化物（HZO）為基礎的FeFET的開關電壓、保久性和耐久性的提升。透過X光光電子能譜儀（X-ray photoelectron spectroscopy，XPS），我們展示了經過氫電漿處理後，能有效降低絕緣層中碳的濃度，從原本的34%降至17.9%，並改善了由氧空缺引起的電荷捕捉現象。氫電漿加速了AlOx 與Si之間的擴散，除了提升絕緣層的介電質外，同時降低了去極化電場，並將崩潰電場的強度從未經過氫電漿處理的11MV/cm提升到12.4MV/cm。此外，經過氫電漿處理的FeFET展現了穩定的讀寫後保久性和改善的耐久性，即使在達到1010次讀寫後也沒有發生故障。最後，我們透過提高溫度來加速元件故障速度，藉此推算元件保久性，我們發現氫電漿處理的元件再搭配上固融體結構的HZO，在高溫下的保久性比傳統矽基FeFET高了18°C，達到97.3°C。這種高溫熱穩定性行為與固融體HfO2/ZrO2有序地排列相關，在這種結構下大幅提升了HZO的熱導性，進而提升了元件的高溫保久性。這項研究對於低功耗FeFET的發展和對FeFET操作的理解具有重要意義。;With the rapid development of fields such as the Internet of Things (IoT), artificial intelligence (AI), and autonomous driving, the demand for storage technology has become
increasingly crucial today. The emerging Non-Volatile Memory (eNVM) will play an indispensable role in the future. The main feature of NVM lies in its capacity to maintain the
original storage state after power-off, while also requiring good scalability, high speed, low power consumption, and excellent reliability. This makes eNVM an essential device of future data storage and processing.
In this work, we focused on common ferroelectric memories within NVM, specifically the Ferroelectric Capacitor (FeCAP) and Ferroelectric Field-Effect Transistor (FeFET). We began with the process of devices, then proceeded to evaluate and compare them through both material analysis and electrical property measurement. Finally, we proposed a method to repair the trapping charges at the interface and effectively remove the unexpected carbon elements generated during low-temperature thin film deposition by utilizing H2 plasma.
We evaluated the effect of remote H2 plasma treatment on improving the performance of FeFETs based on HfZrO (HZO). Through X-ray photoelectron spectroscopy (XPS), H2 plasma reduced the C concentration in the insulating layer, effectively decreasing it from the original 34% to 17.9%. This treatment also improved the trapping charge caused by
oxygen vacancies. It accelerated oxygen diffusion between AlOx and Si, enhancing the dielectric properties of the interfacial layer. Moreover, it increased the breakdown field from 11MV/cm to 12.4MV/cm compared to untreated samples. Furthermore, the H2 plasma-treated FeFET exhibited stable retention and improved endurance, with no failures occurring even after reaching 1010 cycles. Finally, to accelerate device failure time, we increased the temperature and estimated device retention. We found that devices treated with H2 plasma paired with a superlattice structure of HZO exhibited 18°C higher retention compared to traditional silicon-based FeFETs, reaching 97.3°C. This high-temperature thermal stability behavior is correlated with the ordered arrangement of the HfO2/ZrO2 super-lattice. In this structure, the thermal conductivity of HZO is significantly enhanced, thereby improving the high-temperature retention of the devices. This research holds significant importance for the development of high-speed, low-power FeFETs and enhances the understanding of FeFET
operation mechanisms. |
