基于扫描电镜和能谱仪的薄膜表面形貌和厚度同时测量研究

Simultaneous Measurement of Thin Film Surface Morphology and Thickness Based on Scanning Electron Microscope and Energy Dispersive Spectrometer

扫描电子显微镜通过电子束轰击样品产生的二次电子、背散射电子等实现对样品表面形貌的观测,通过对样品横断面的观测来获得薄膜厚度信息,但难以实现对薄膜表面形貌和厚度的同时观测。通过能谱仪研究各种厚度的薄膜同其激发的特征X射线计数率之间的关系,实现了通过特征X射线计数率来测量薄膜厚度的方法。对于激光吹气系统所需的钨薄膜而言,结果表明,计数率随薄膜厚度的增加先线性增加后趋于稳定,利用该曲线的直线部分作为刻度曲线,可实现对5~19μm范围内钨薄膜表面形貌和厚度的同时测量,精度约为10%,通过增加电子能量可实现对更厚样品的测量。该方法可推广到其他种类的薄膜研究,有助于推动薄膜物理研究的开展。

The scanning electron microscope can observe the surface morphology of the sample through the secondary electrons and backscattered electrons produced by the electron beam bombardment.The thickness information of the film can be obtained by observing the cross section of the sample,but it is difficult to observe the surface morphology and thickness of the film at the same time.The relationship between various thickness films and their excited characteristic X-ray counting rate is studied by energy dispersive spectrometer,and the measurement of film thickness by characteristic X-ray counting rate is realized.The results show that the counting rate first increases linearly and then tends to be stable with the increase of the film thickness.Using the linear part of the curve as the calibration curve,the simultaneous measurement of the surface morphology and thickness of the tungsten film in the range of 5-19μm can be realized,and the accuracy is about 10%.The measurement of thicker samples can be realized by increasing the electronic energy.This method can be extended to other kinds of thin film research,and is helpful to promote the development of thin film physics research.