氮化鋁MIS 薄膜電容之研製與特性分析

Abstract

本實驗採用射頻磁控濺鍍系統沉積氮化鋁(Aluminum Nitride，AlN)薄膜，在相同的濺鍍壓力下，改變氬氣和氮氣之流量比，製成氮流量比分別為10%至60%之氮化鋁薄膜，薄膜的結晶由XRD繞射分析，並由AFM來觀察其表面型態，然後觀察並量測薄膜之物理特性。 實驗結果得知，以氮流量50%之氮化鋁薄膜為薄膜電容之介電層時，初步經XRD及FTIR分析顯示在1500W濺鍍功率與50%氮流量，越容易沈積(002)從優取向氮化鋁薄膜，乃因越高能量的濺鍍原子對形成(002)表面越有利。以氮流量50%之氮化鋁薄膜為介電層時，有較好的電容值。若氮化鋁薄膜再經過氧氣電漿處理之後，其電氣特性會明顯提升，亦即有更大之電容值。

As the feature size of silicon-based devices shrinks below 0.18 μm, the need for new electronic materials becomes readily apparent. Aluminum nitride is an attractive material for this purpose due to its significantly higher dielectric constant and its good thermal expansively match with silicon at the operating temperature of p-MOS and n-MOS devices. Aluminum nitride thin films grown on SiO2/Silicon substrate by RF magnetron sputtering using 10%~60% nitrogen concentrations in a mixture with argon has been studied. Simple MIS capacitor was fabricated in order to evaluate the electrical properties of AlN films that played as a insulator. The microstructures of the AlN films were examined by X-ray diffraction. The observation of the surface morphology and roughness were performed by scanning electron microscopy and atomic force microscopy. The experimental results showed that the (002) orientation AlN thin films and best capacitance performances of 50% nitrogen concentrations were obtained with 1500W sputtering power and 3 mtorr working pressure conditions. The O2 plasma treating can greatly improve the AlN film’s electrical properties.