高功率脈衝磁控濺鍍二氧化鋯介電層於金氧半電容之性質研究

Abstract

高功率脈衝磁控濺鍍 (High Power Impulse Magnetron Sputtering, HIPIMS)是目前最新的濺鍍製膜技術，與傳統的直流磁控濺鍍 (Dielectric Current Magnetron Sputtering, DCMS)相比，HIPIMS有著在極短的脈衝時間內讓靶材單位功率密度達到數 kW/cm2以上的特性，另外還能產生出很高的電漿密度並有效增加靶材金屬離化率，生成的薄膜也有著較好的品質，因為這些特質，本研究將使用 HIPIMS與 DCMS系統分別沉積 MOS電容中的介電層。 二氧化鋯是一具有高介電係數 (約在19-25之間)、寬能隙寬能隙 (5.1-7.8 eV)及高熱穩定度之特性的材料，因此選擇二氧化鋯去做為試片的介電層，最後再鍍上TiN作為金屬層，在 800度的快速熱退火之後，觀察該電容器的物性。接著，對試片電容沉積鋁電極以量測電性，因此本研究的試片結構為Al/ TiN/ ZrO2/ p-Si。實驗結果顯示HIPIMS技術優秀的離子解離率可以使ZrO2的結構更加完整、內部的缺陷也比較少，因此有比較好的電容值表現。物性方面，HIPIMS所濺鍍出的電容一樣會形成更加緻密的薄膜進而提高其機械性質，在硬度值有所增加，有效的改善薄膜硬度。 最後，綜合作比較，可以發現雖然電容值與硬度兩者的改變差異沒有完全的相同，但是在整個趨勢上是相當近似的，因此從量測介電層的硬度就可以推測出電容值的走向，而電容值的改變也可以進一步推斷出IDsat的趨勢，如此就可以於完成製作 MOSFET電晶體前，提前達到製程優化。High Power Impulse Magnetron Sputtering (HIPIMS) is the latest coating technology. Compared with the traditional Dielectric Current Magnetron Sputtering (DCMS), it was characterized for a very short pulse width making peak power density to several kW/cm2. In addition, HIPIMS can provide high plasma density (1019 m-3) and high metallic-ion density. Because of these characteristics, this study used both HIPIMS and DCMS to deposit the dielectric layer on the MOS capacitors. ZrO2 is a material with the properties of high dielectric constant (~19-25), wide band gap (5.1-7.8 eV), and stable thermal stability. So we selected ZrO2 as the dielectric layer of MOS capacitors and TiN as the metal layer. After rapid thermal annealing (RTA) annealing at 800 ℃, we observed the physical characteristics of MOS capacitors. Then we coated aluminum as the electrode, followed by measurement of electrical properties. Hence the structure of the MOS capacitors is Al/ TiN/ ZrO2/ p-Si. The results showed that the ionization of HIPIMS can improve the quality of ZrO2 layers and therefore the capacitors result in a better electrical property. Moreover, HIPIMS also effectively increase the film hardness.