In-Situ Thickness Measurement System for Porous Alumina Film Based on AFM and Spectrometer

An atomic force microscope (AFM) and spectrometer combined system for in-situ thickness measurement of nano-porous alumina (PA) films is introduced. The AFM is applied to obtain the porosity of PA film, and then we calculate the effective refractive index by Maxwell-Garnett effective dielectric constant theory. The optical thickness of PA film is determined by reflective interference spectrometer. The PA film thickness can also be measured via scanning the crosssection with optical microscope and scanning electron microscope (SEM). The sample will be damaged, however, when using this method. The measurement by optical microscope is convenient, but it’s hard to attain high resolution. When using SEM, the sample surface must be gilt and needs a vacuum environment. The system we developed can avoid the disadvantages of the method. It realizes non-destructive and highresolution in-situ measurement.