利用田口法優化高介電係數鋁氧化鉿薄膜特性

Abstract

本研究主要是將田口法應用在尋找高介電係數薄膜鋁氧化鉿之優化參數配方。 氧化鉿高介電係材料其結晶溫度過低，大幅降低於實務運用上之可能性，所以透過摻雜鋁提升結晶溫度並於XRD中證明其是有效的。首先適當選擇對薄膜品質特性之影響因子與變動水準，再藉由田口直交表所安排之參數配方製作以鋁氧化鉿薄膜為基礎之鋁/鋁氧化鉿/P型矽基板結構之電容器，量測其電壓-電流與電壓-電容特性曲線，並將針對不同之品質特性，使用適當之訊雜比公式，依據其所計算之數值選取每個變動因子之最佳水準數。 再將所選取之優化配方與田口直交表內所有配方做比較，經過電壓-電流特性曲線、電壓-電容特性曲線、XRR、AFM的量測分析，證實利用田口法所尋找之優化配方在漏電流或是電容值方面的品質特性比傳統實驗設計法更有效率且也確保了優化的精準性。

The purpose of this study is to apply Taguchi method for recipe optimization of high-k HfAlO thin-films. It is known that the crystallization temperature of HfO2 thin-films is relatively low and this limits the applications of HfO2 thin-films. In this study, aluminum has been doped in HfO2 films to raise the crystallization temperature, which was verified by XRD. First, the effect factors and their levels with regard to the film characteristics were selected. Then the MOS capacitors (Al/HfAlO/p-Si) were manufactured according to the Taguchi orthogonal array (OA). Finally, I-V (current-voltage) and C-V (capacitance-voltage) measurements were made and evaluated. Based on the electrical measurements, signal/noise (S/N) ratios were calculated the optimal level of each factor was accordingly selected. In order to verify the validity of this method, I-V, C-V, XRR, and AFM characteristics of the resultant recipe (i.e. combination of optimal levels of all factors) were also compared with those of the recipes shown on Taguchi orthogonal array. Based on the results of this study, it can be concluded that the capacitance and leakage characteristics of high-k thin-films can be significantly improved through Taguchi method efficiently.