低电压驱动微流控芯片二氧化硅绝缘薄膜的研究

The study of SiO_2 insulating film for low voltage-driven microfluidic chip

采用电子束蒸发法在玻璃基底上制备了二氧化硅薄膜,利用原子力显微镜(AFM)、台阶仪、X射线衍射仪(XRD),分别对不同条件下制备的二氧化硅薄膜的表面形貌、膜厚、结构进行了表征,并采用金属/绝缘膜/金属(MIM)结构对薄膜的I-V电学特性进行了分析。结果表明玻璃基底温度在300℃条件下生长的4μm厚度的二氧化硅薄膜,其表面均匀平整,耐压能力>200V,能够承受500kV/cm以上的场强,满足作为低电压驱动微流控芯片绝缘薄膜的要求,并在样品驱动的应用中得到验证。

The silicon dioxide （SiO2） insulating film was fabricated by electron-beam evaporation technique. Different conditions of preparation for the SiO2 film were studied. Micro-morphology, depth and compositions of SiO2 film was investigated by AFM, step profiler and XRD. The electrical properties of the film were determined by measuring Ⅰ-Ⅴ characteristics in a metal-insulator-metal （MIM） structure. The results showed that when the substrate temperature was at 300℃ and the thickness of SiO2 film was 4/Lm, the surface of the film is smooth and uniform, The breakdown voltage is higher than 200V and breakdown strength is greater than 500kV/cm. It meets the requirements of the insulating film for the low voltage-driven micro-fluidic chip and has been validated through the practical experiment of the sample driven.