以高介電值材料作為矽基板上閘極介電層之研製與特性分析

Characteristic Study of MIS Capacitors Using Sputtered High-K Film as Gate Dielectrics

蔡文哲(Wen-Che Tsai)

指導教授 ： 高慧玲

中原大學/工學院/電子工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400297

摘要

為了增加元件的速度和效能，使得元件的尺寸必須不斷的縮小以增加積集度，同時也為了避免短通道效應的出現，其閘氧化層的微縮速率，超出許多專家的預期提早到達了物理極限的範圍。以70奈米的技術來說，閘極氧化層的厚度僅在0.7至1.2奈米左右。
而透過許多應用上的要求也往往限制了厚度持續微縮的可行性，其中包括(一)直接穿隧：造成元件產生大量的漏電流。(二)遷移率下降：因厚度的減少使得垂直電場增加，等電性限制。因此利用高介電常數材料取代現今的二氧化矽成為不可避免的趨勢。
本研究中，利用射頻磁控濺鍍系統所沉積的氧化釔(Y2O3)與迴旋濺鍍系統沉積的氮化鋁(AlN)作為MIS電容器中的閘氧化層，透過C-V、I-V等電性量測，得到兩種材料的介電常數在厚度微縮至100A以下有明顯的下降、閘極漏電流密度在厚度70~170A左右約為10-7~10-8A/cm2( @1V )，而兩種材料的介面態密度值(midgap)則約為 1011eV-1cm-2至於與陷捕電荷量相關的磁滯曲線寬度則以氧化釔的60mV為最佳值(2.9×1011cm-2)，最後根據這些量測結果，分析並予以討論高介電材料成為閘氧化層的可行性與其瓶頸所在。而研究中並特別探討C-V量測所需特別處理及注意之技術以確保量測結果的準確性。

關鍵字

高介電值材料 ； C-V量測 ； 迴旋濺鍍系統 ； 射頻磁控濺鍍系統

並列摘要

The dimension of electronic devices has shrunk continuously. To avoid short channel effects, the scaling rate of oxide thickness has already reached physical limit faster than experts predicted. In 70nm technology node, gate oxide thickness is merely in the range of 0.7~1.2nm.
Various practical issues may limit the thickness scaling as well. These include power dissipation due to direct tunneling, the degradation of mobility due to increasing vertical electrical field, etc. Using a new material with a dielectric constant greater than that of SiO2 to replace SiO2 film as gate dielectrics is an indispensable task.
In this research, we report the C-V、I-V electrical measurement results of MIS capacitors using Y2O3 thin film deposited by RF magnetron sputter system and AlN deposited by Helicon sputtering system. The leakage current density of 10-7~10-8A/cm2 at 1V was obtained for physical thickness around 70~170A. The Dit at midgap for Y2O3 and AlN were about 1011eV-1cm-2. The optimized hysteresis(ΔVh) is about 60mV for Y2O3(2.9×1011cm-2). According to the above results, we discuss the feasibility and necks about the high-k materials to be new gate dielectrics. In the study, I also verify and conclude the C-V measurement technique to make research results accurately.

並列關鍵字

helicon sputtering system ； high-k materials ； RF magnetron sputter system ； C-V measurements

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