臺灣博碩士論文加值系統

在非揮發性記憶體的發展與研究過程中，矽-氧化矽-氮化矽-氧化矽-矽(Silicon-Oxide-Nitride-Oxide-Silicon，SONOS)記憶體元件具有許多優點備受矚目。然而隨著尺寸的微縮以及為了維持良好的儲存能力，各種材料及結構也被使用在SONOS結構裡用以改善可靠度的相關問題。
本篇論文提出一種新穎的SONOS儲存單元製造之方法。首先，我們在試片上成長一層薄的化學氧化層（chemical oxide）；接著使用LPCVD通入NH3氮化化學氧化層，然後沈積氮化矽層；之後使用爐管通入O2對氮化矽層進行再氧化。優點在於LPCVD可同時氮化化學氧化層以及沈積氮化矽；而再氧化過程中，可趕走氮化穿遂氧化層所產生的氫，使得穿遂氧化層表面形成具高氮濃度的氮氧化層，同時使得氮化矽層形成具漸變式梯形能帶的結構。另外探討不同再氧化時間對於可靠度特性的影響。研究結果發現，經過再氧化處理之後，在適當的條件下，確實能有效增大記憶體操作窗口，並且減緩寫入、抹除等操作所造成性能退化的速率。

Nowadays, SONOS (Silicon-Oxide-Nitride-Oxide-Silicon) memory device becomes popular because of its simplicity and scalable in structure by comparing with conventional floating gate flash memory.
In this thesis, we proposed a novel process to fabricate a SONOS capacitor. This process mainly included four process stages – chemical oxide growth, nitridation, forming the Si3N4 and subsequent furnace O2 reoxidation. By this process, the oxynitride as tunnel dielectric and a tapered bandgap nitride are obtained.
It is found that the structure formed by this novel process exhibits improved cycling endurance and charge-trapping efficiency. The result of the experiment can provide a very promising solution for future flash memory design.

Abstract (Chinese) …………………………………………i
Abstract (English) …………………………………………ii
Acknowledgment (Chinese) …………………………………iii
Contents ………………………………………………………iv

Chapter.1 Introduction of Non-Volatile Memory
1.1 General Background ………………………………………1
1.2 Motivation …………………………………………………3
1.3 Organization of This Thesis……………………………4

Chapter.2 Basic principles of SONOS memory
2.1 Introduction ………………………………………………8
2.2 Operation Mode ……………………………………………8
2.3 Reliability ………………………………………………10
2.4 Summary ……………………………………………………12

Chapter.3 Experimental Process and discussion of results
3.1 Introduction………………………………………………17
3.2 Experimental Process……………………………………18
3.3 Discussion of Results …………………………………20
3.4 Summary ……………………………………………………23

Chapter.4 Conclusion and suggestion of future work
4.1 Conclusion…………………………………………………45
4.2 Suggestion of Future Work ……………………………45

References………………………………………………………47
Vita………………………………………………………………51

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