氟 與 氮 對 超 薄 氧 化 層 可 靠 度 之 研 究

Abstract

利用離子佈植的方式將氟與氮植入到閘極氧化層以及矽基座，以探討氟與氮對閘極氧化層可靠度之效應。在研究中發現，有氟摻雜在閘極氧化層的元件，其在電導、次臨界擺幅的表現上都比一般元件有些許改善。另外氟化及氮化氧化層也能有效抵抗熱載子所造成的損害。在電荷累積崩潰分布的面積效應上，發現氟原子累積在多晶矽層與閘氧化層的介面之間，是造成大面積元件其電荷累積崩潰分布嚴重衰退的原因。 另外將氟與氮植入到矽基座再成長氧化層，可同時得到不同的氧化層厚度，但是在N2O氮化的氧化層中，其厚度效應就沒有一般O2氧化層要來得明顯。在電漿充電損害效應方面，一般O2氧化層的元件藉由適量的氟與氮摻雜可有效抑制電漿充電損害。但是在N2O氮化的氧化層中，只有單獨將氟佈植在矽基座的元件才能得到有效改善。最後我們也提出一個假設性的模型來說明氟化及氮化氧化層可有效改善電漿充電損害的原因。

The effects of fluorine and nitrogen incorporation on ultra-thin gate oxide integrity (GOI) were investigated by implanting fluorine and nitrogen into poly gate or Si substrate. The transconductance (Gm) and subthreshold swing (S.S) of fluorinated devices were better than that of nitrided devices. The hot carrier reliability test also showed that fluorinated oxide was more resistant to hot electron injection. For area dependence of charge-to-breakdown, the fluorine atoms pile up at the poly-Si/SiO2 interface may be responsible for degradation in large gate area devices. It is observed that fluorine and nitrogen implantation into Si substrate prior to oxidation can be used to obtain multiple oxide thickness, albeit its effectiveness is drastically reduced for N2O-nitrided oxide. Gate leakage measurements performed on antenna devices show that charging damage can be significantly reduced for fluorine- or nitrogen- implanted devices with O2 oxide. On the other hand, fluorine-alone implant is useful to reduce the gate leakage of antenna devices with N2O oxide. Finally, the possible model for immunity to plasma charging damage was proposed. Abstract(English)……………………………………………………………………………Ⅱ Acknowledge…………………………………………………………… Ⅲ Contents…………………………………………………………………Ⅳ Figure Captions…………………………………………………………………Ⅴ Chapter1 Introduction……………………………………………………………1 1-1 Background and Motivation………………………………1 1-1-1 The Fluorine Engineering in CMOS Technology…1 1-1-2 The Nitrogen Engineering in CMOS Technology…4 1-1-3 The Effect of Plasma Charging Damage in Ultra Thin nitrided Oxide...5 1-2 Organization of the Thesis………………………………………6 Chapter2 Experiment Description……………………………………7 2-1Fabrication Process for Test Structure………………………7 2-2 Measurement Techniques…………………………………………10 2-2-1 Ultra-Thin Gate Oxide Thickness Measurement…………10 2-2-2 Hot-Carrier Stress Measurement……………………………11 2-2-3 C-V Measurement…………………………………………………12 2-2-4 I-V Characteristics……………………………………………12 2-2-5 Time-Dependent Dielectric Breakdown (TDDB) Method……12 Chapter 3 Study of Fluorine and Nitrogen incorporation into Ultra-Thin Gate Oxide for nMOSFET…………........13 3-1 Multiple Oxide Thickness for Fluorine and Nitrogen Implan.................................................13 3-1-1 Introduction……………………………………………………13 3-1-2 Experimental Results…………………………………………13 3-1-3 The Possible Mechanism of Fluorine and Nitrogen Modulate the Oxide Thickness……………………………………………14 3-2 Evaluate Performance Assessment of n-MOSFET with Fluorine and Nitrogen Implantation………………………………………................15 3-3 Hot Carrier Reliability……………………………………………..............17 3-3-1 Introduction………………………………………………………17 3-3-2 Experimental Results…………………………………………17 3-3-3 The Possible Mechanism of Hot Carrier Immunity for Fluorinated and Nitrided Oxide…………………………....18 3-4 Area Dependence of Charge to Breakdown……………………20 Chapter 4 Plasma Charging Immunity Using Fluorine and Nitrogen Implantation………………………………………………22 4-1 Introduction…………………………………………………………22 4-2 Plasma Charging Damage in Fluorine- and Nitrogen-Implanted Oxides…...22 4-3 Proposed Model for the Immunity to Process-Induced Damage………24 Chapter 5 Conclusions and Suggestions for Future work……………………26