Golden coating optimization for better characterization of non conductive samples

Full text: The enlarged image obtaining by scanning electron microscopy results from the interaction of electron beams with the material. Non-conductive samples require previous treatment in the surface, usually it can be made with the deposition of an ultra-thin film of conductive material such as Gold (Au). Deposition by sputtering is the process most commonly used for this purpose, despite having fairly high cost. Based on that, this study aims to optimize the metal coating time, optimizing the Au consumption and the additional cost of the process without affecting the image final quality. Characterization was carried out by Electron Probe Micro- Analysis (EPMA), chemical micro-analysis by Energy Dispersive Spectroscopy (EDS) and gold coating detected by X-Ray Diffraction (XRD) and Spectroscopy X-Ray Fluorescence using wavelength (XRF -WD). Three types of patterns were used for this study: boric acid (H₃BO₃), iron oxide III (Fe₃O₄) and silicon monocrystal. The gold was deposited by sputtering starting from samples without metallization until 2 minutes, varying 5 seconds of each coating. It was noted that with the metallization time progress, there was a reduction of the surface electrons loading improving Fe₃O₄ and H₃BO₃ image quality and a evolution of the Au detection. EDS micro-analysis technique was more sensitive to thin film than the WDS technique. The X-ray diffraction was also sensitive to the deposition from 15 seconds coating. (author)