氮植入閘極氧化層之元件特性

為了達到高性能和低電壓之元件，減少閘極氧化層厚度是現代超大型積體電路工業的一個主流。目前有釵h種方法可獲得超薄閘極氧化層，在閘極氧化之前先進行氮植入是一種有名的製作超薄閘極氧化層技術，藉由這種技術，系統單晶片(SOC)之製程技術變得可行。因此，此論文主要討論氮植入閘極氧化層之元件特性。第一章將針對氮植入閘極氧化層之實驗做個介紹，元件製作過程、元件結構和量測儀器均會被介紹以了解本實驗之背景。第二章主要探討氮植入閘極氧化層之厚度效應，在不同的氮離子植入劑量並搭配不同的氧化溫度所產生之厚度變化將會做個調查，藉由SIMS分析，吾人可了解在矽底材之氮摻雜物之濃度分佈曲線圖，然後提出一個機制來解釋氮植入可抑制閘極氧化之特性。第三章將分析氮植入閘極氧化層之電容-電壓效應。首先描述基本的理論以便明瞭後續實驗結果的特性，然後量測不同頻率下的閘極電容並且比較之，從電容-電壓關係圖可以得到平能帶電壓和介面缺陷電荷密度結果，根據高頻閘極電容結果可以得到硼摻雜物在矽底材之分佈圖，進而證明氮植入具有抑制硼滲透效應。第四章將分析氮植入閘極氧化層之另一電氣效應，電流-電壓關係式。直接穿隧電流和F-N穿隧電流理論將被探討以了解其機制；直接穿隧電流之實驗結果和F-N穿隧電流之實驗結果將被個別討論，以了解不同的形成原因。經由閘極穿隧電流均勻度結果，吾人可了解氮植入閘極氧化層之厚度均勻度效應。另外，從F-N穿隧電流結果，可以比較出能帶障礙高度，並進而了解何種條件可造成低障礙高度並導致高閘極漏電流。最後，第五章將是本論文之結論。

關鍵字

氮植入；氧化層

並列摘要

To obtain high performance and low power device, gate oxide thickness shrinkage is a main stream in modern ULSI industry. There are many approaches to achieve ultra thin gate oxide in the state of art. Nitrogen implantation prior to gate oxidation is one of the famous techniques in ultra-thin oxide engineering. With this technique, SOC process becomes feasible. In this thesis, we are going to discuss the characteristics of nitrogen implanted gate oxide. Chapter one is an introduction of nitrogen implanted gate oxide experiment. The process flow design, device structure and measurement tool are also introduced to realize this experimental background. The oxide thickness effect of different nitrogen implantation dosage is described in chapter 2. The oxide thickness result of process combinations of different dosage and different oxidation temperature are investigated. And by way of SIMS analysis, we can figure out the nitrogen dopant profile in Si substrate. Then we propose a mechanism to explain the oxidation retardation effect due to nitrogen implantation. Chapter 3 is the C-V characteristics of nitrogen implanted gate oxide. Basic theory is described first to understand the following properties well. Different frequencies of gate capacitance are measured for comparison. The flat band voltage and interface trap density can be extracted from the C-V plot. According to high frequency capacitance result, the boron doping distribution in Si substrate is used to examine the effect of boron penetration suppression. Chapter 4 is the I-V characteristics of nitrogen implanted gate oxide. The theory of direct and F-N tunneling current is introduced to realize the mechanism. According to the gate current result, the direct tunneling and F-N tunneling regime will be discussed. From gate tunneling current uniformity result, we also realize the oxide thickness uniformity performance of nitrogen implantation. From F-N tunneling current, the barrier height is extracted. It gives the information of the possible process that introduces a low barrier height and therefore results in a high gate leakage current. Finally, the conclusion of this study is given in chapter 5.

並列關鍵字

Gate Oxide ； Nitrogen implantation

參考文獻

[1] H. R. Soleimani, B. S. Doyle, and A. Philipossian, “ Formation of ultrathin nitrided SiO2 oxides by direct nitrogen implantation into silicon,” J. Electrochem. Soc., vol. 142, no. 8, p. L132, 1995

[2] Liu, C.T. and Ma, Y. et al. “ Multiple Gate Oxide Thickness for 2GHz System-on-A-Chip Technologies ”, IEDM 1998

[3] In-Ho Nam et al.; “ Ultrathin gate oxide grown on nitrogen-implanted silicon for deep submicron CMOS transistors ” Electron Devices, IEEE Transactions on , Volume: 48 , Issue: 10 , Oct. 2001

[4] Liu, C.T. et al.; “Light Nitrogen Implant for Preparing Thin-Gate Oxides ” IEEE Electron device letters, Vol. 18,No 3, March 1997

[6] Chao, T.S.; Chen, J.L.; Lai, C.S.; Lin, H.C.; Huang, T.Y.;” High quality ultra-thin (2.4 nm) oxide prepared by clustered vertical furnace” VLSI Technology, Systems, and Applications, 1999. International Symposium on , 8-10 June 1999

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氮植入閘極氧化層之元件特性

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