非揮發性記憶體奈米尺寸陷阱物理暨相關可靠性物理之嶄新研究

Abstract

本計劃為期三年，進行非揮發性記憶體奈米尺寸陷阱物理暨相關可靠性物理之嶄新研究。 第一年以我們的 2005 年Physical Review-B 奈米尺寸陷阱物理論文為基礎，實驗決定0.15 um 製程快閃式記憶體tunnel 氧化層中中奈米尺寸陷阱的能量系統圖，此快閃式記憶體由學術界 合作對像以及記憶體知名大廠等提供。同時進行電性量測快閃式記憶體元件的特性以及長時 間加速劣化實驗 (作法可參考我們的2005 年IEEE TED 快閃式記憶體論文) ，以進行可靠性 物理研究。此可靠性物理即是整合我們的歷年來於氧化層陷阱物理機制以及快閃式記憶體相 關議題發表的論文並予以應用，自然也包括我們的Physical Review-B 奈米尺寸陷阱物理論文 之應用。 也要積極針對我們的奈米尺寸陷阱物理論文所建立的基礎，理論上作一個更為深入 的研究建立一牽涉波函數的量子力學數值模式， 得以在同一能量系統下整合奈米尺寸陷阱和 氧化層中量子點或量子晶體物理。第二年繼續電性量測快閃式記憶體元件的特性以及長時間 加速劣化實驗，進行可靠性物理深入研究。此第二年的快閃式記憶體元件應為 0.13 um 製程 者。繼續從學術界合作對像取得更多快閃式記憶體測試元件。 也進行Hall 效應量測，提供較 深入的實驗數據。延續氧化層奈米尺寸陷阱物理研究，進一步應用於快閃記憶體，即針對氧化 層中量子點或量子晶體，利用波函數及能量系統分佈的角度來處理，相互比較並將之關聯。第 三年 繼續電性量測0.11 um 或 90 nm 製程快閃式記憶體元件的特性以及長時間加速劣化實 驗，進行可靠性物理深入研究。前兩年理論應用結果送至學術界合作對像以及國際知名大廠等 參考以為實際研發較具實用的次世代快閃記憶體。也繼續Hall 效應量測以及次臨界級雜訊量 測，再度深一層驗證理論。最後一年裡，積極應用嚴謹的牽涉波函數的量子力學數值模式 (可 以在同一能量系統下整合奈米尺寸陷阱和氧化層中量子點或量子晶體物理): 藉由自我量測數 據及論文數據比較，對於不同尺寸元件結構進行比較分析，並對下世代元件走向及應用潛力作 一預估，且要探討量子點在氧化層中位置分佈對於整體系統的特性影響，更考慮在高溫操作 下，資料保存的正確無誤，以此作為設計電路的基礎經驗，並嘗試提出設計的最佳化以供次世 代快閃記憶體電路設計之用。

This is a three-years project devoted to investigating the nanometer scale trap physics as well as reliability physics in nonvolatile memory. In the first year, the energy system associated with the nanoscale trap in tunnel oxide of 0.15 um Flash memory will be experimentally established on the basis of our 2005 Physical Review –B article addressing the underlying trap physics. Flash memory test-key will be provided from such collaborators as Silicon Storage Technology (in Taiwan and the US) and the colleagues in certain universities. Meanwhile, electrical characterizations as well as long-term accelerated degradation experiment (refer to our 2005 IEEE TED Flash memory paper) will be carried out such as to accommodate study on reliability physics. The reliability physics here is involved with our series of publications over many years on the oxide trap mechanism and Flash memory related issues. The published 2005 Physical Review-B paper is also included as well. Furthermore, we want to extend the nanoscale trap physics by building up a comprehensive wavefunction based quantum mechanical numerical model. Then under the same energy system, we can consistently deal with quantum dot or nanocrystal physics in the oxide. In the second year, we continue the way but on the next-generation 0.13 um Flash memory. More test-key will be possible from more colleague collaborators. Also conducted are Hall effect characterizations to provide useful data. Actual extension to the case of quantum dots or nanocrystals in memory case will be demonstrated. In the third year, we again continue the study but on the 0.11 um or 90 nm Flash memory along with long-term reliability test and physics. The promising results over the years will be returned back to collaborators for actual improvements and/or more implementation of potential applications. Both Hall effect and subthreshold noise experiment will be performed to check the model. Within this final year, we will take serious action to make use of the wavefunction based quantum mechanical numerical model associated with nanoscale traps, quantum dots, or nanocrystals: (i) with experimental data of our own and those in the literature, a comparative study will be produced on different Flash memory cell structures; (ii) the trend and potential applications of next-generation Flash memories will be drawn accordingly; (iii) the distributions of quantum dots are vital and will be addressed from a novel standpoint; and (iv) especially at high temperature of operation (with bake data as input), the measured retention characteristics will be reproduced with the model, which can in turn lead to optimum design of next-generation Flash memory concerning different aspects: the cell, the circuit, and the array.