Electronic Film Electron Probe Spectroscopy Analysis Technique

Microstructure, component and thickness are key factors to determine the performances in research of thin films. The methods to characterize microstructure, component and thickness of thin fihns are all through important issues in thin films field, especially the non-destructive characterization. The observation of microstructure, analysis of components in tiny regions and measurement of thickness according to penetration depth can be realized with Scanning Electron Microscope and X-ray Energy Dispersive Spectrometer (EPMA), while any other thin film-analyzing approaches don't possess the above three function simultaneously.Using EPMA analysis technique, when thickness of thin films is less, the spectrum line of thin film and substrate appears at the same time, which affects the element analysis results of thin films severely. To eliminate the interference from substrate spectrum, this paper discuss the following research means, aiming at analyzing and characterizing the micro- and nano-materials of thin films in the State Key Laboratory of Electronic Thin Films and Integrated Devices.1. Based on the general EPMA system, grazing-exit EPMA (GE-EMPA) analysissystem is set up and evaluated systematically. Through qualitative analysis between the GE-EMPA and general EMPA of Cu metal thin film and ZnO semiconductor thin film adulterated with Cd, different characteristic X-ray intensity with different exit angle, the effect of incline to the quantitative analysis of electron probe spectrum, and some other studies, this method is proved to solve many problems of analyzing general electron probe exit of thin films, such as depth decrease of electron effect range, good surface sensitivity, fluorescence effect from the substrate dropping to the bottom, increased precision of quantitative analysis for thin films, etc.2. The methods for improving analysis precision of thin fihns are demonstrated with general EMPA analysis technique. From the X-ray spectrum analysis of thin films, it's found that-different characteristic X-ray line of one element is a factor that impacts the analysis result most. For thin films and substrate with fluorescence effect, if any element is affected by fluorescence from substrate, characteristic X-ray line of the chose elements should have fluorescence effect from the substrate. For thin films and substrate without fluorescence effect-with enough overvoltage ratio, the biggest peak to background ratio (P/B) should be chose; when the characteristic X-ray line is chose exactly, the bigger work voltage is, the more precise analysis result.3. Thickness measurement of thin films with EMPA is investigated. According to the penetration depth of electron beam, thickness of thin films is calculated. For the thin film with single element, with extrapolating the characteristic X-ray peak ratio of substrate to thin film to "0", the corresponding accelerating voltage is the normalization voltage Ed (the characteristic X-ray of substrate can't be tested at the beginning). For thin films with many elements, if the thin film and substrate have same elements, the relationship between accelerating voltage and element intensity ratio of thin film to substrate, as well as the relationship between accelerating voltage and standard bulk pattern can be got. The change speed of characteristic X-ray peak ratio of substrate to thin film and standard bulk are identical, the corresponding accelerating voltage is the normalization voltage Ed.4. Quantitative analysis of light elements of thin films is implemented with EMPA. Through adjusting the position of low energy peak marked with light element, low energy peak and simulation line inosculate primely. With decreasing work voltage gradually until electron penetration depth and thickness of thin films are identical, the effect of substrate and surface absorption can be reduced furthest, combining with SEC factor in EDAX spectrum analysis software, satisfactory analysis consequences can be obtained.