磁控共溅射法沉积的硅量子点SiN x薄膜的光谱特性

摘要

采用双极脉冲和射频磁控共溅射沉积法在不同温度的Si（100）衬底和石英衬底上制备了富硅SiNx薄膜。在氮气氛中，于1050℃下采用快速光热退火热处理，获得了包含硅量子点的SiNx 薄膜。采用 Fou‐rier变换红外光谱、Raman光谱、掠入射X射线衍射和光致发光光谱对退火后的薄膜样品进行了表征。结果显示：Fourier变换红外光谱中出现了富硅Si—N键，表明薄膜为富硅SiN x 薄膜；当衬底温度不低于200℃时，薄膜样品的拉曼光谱中出现了硅纳米晶的Si—Si振动横光学模，掠入射X射线衍射中出现了明显的Si （111）和Si（311）的衍射峰，证实了硅量子点的形成；发现存在一最佳衬底温度（300℃），该条件下获得的硅量子点的数量和晶化率最高；衬底温度为300和400℃的样品的光致发光光谱中均有3个可见荧光峰，结合拉曼光谱结果，用纳米晶硅的量子限域效应和辐射复合缺陷态对荧光峰进行了合理解释；由光致发光光谱计算出的衬底温度为300和400℃的样品的硅量子点平均尺寸分别为3.5和3.4 nm。这些结果有助于优化含硅量子点的SiN x 薄膜的制备参数，在硅基光电子器件的应用方面有重要意义。%The silicon‐rich SiNx films were fabricated on Si(100) substrate and quartz substrate at different substrate tempera‐tures varying from room temperature to 400 ℃ by bipolar pulse ane RF magnetron co‐sputtering deposition technique .After dep‐osition ,the films were annealed in a nitrogen atmosphere by rapid photo‐thermal annealing at 1 050 ℃ for 3 minutes .This ther‐mal step allows the formation of the silicon quantum dots .Fourier transform infrared spectroscopy ,Raman spectroscopy ,graz‐ing incidence X‐ray diffraction and photoluminescence spectroscopy were used to analyze the bonding configurations ,microstruc‐tures and luminescence properties of the films .The experimental results showed that :silicon‐rich Si‐N bonds were found in Fou‐rier transform infrared spectra ,suggesting that the silicon‐rich SiNx films were successfully prepared ;when the substrate tem‐perature was not lower than 200 ℃ ,the Raman spectra of the films showed the transverse optical mode of Si‐Si vibration ,while the significant diffraction peaks of Si(111) and Si(311) were shown in grazing incidence X‐ray diffraction spectra ,confirming the formation of silicon quantum dots ;our work indicated that there was an optimal substrate temperature (300 ℃) ,which could significantly increase the amount and the crystalline volume fraction of silicon quantum dots ;three visible photoluminescence bands can be obtained for both 300 ℃ sample and 400 ℃ sample ,and in combination with Raman results ,the emission peaks were reasonably explained by using the quantum confinement effect and radiative recombination defect state of Si nanocrystals ;the average size of the silicon quantum dots is 3.5 and 3.4 nm for the 300 ℃ sample and 400 ℃ sample ,respectively .These re‐sults are useful for optimizing the fabrication parameters of silicon quantum dots embedded in SiN x thin films and have valuable implications for silicon based photoelectric device applications .