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Equipment designed with combined capabilities to perform both sputtering and carbon evaporation procedures to form an even coating of metal or carbon on the surface of a sample to be observed using an electron microscope. Sputtering is the process of bombarding a material with heavy atoms or ions with sufficient energy to dislodge and transfer the material to a different location. A high voltage creates a charge at the target surface and at the same time strips an electron from the sputtering gas (usually argon). Since the target has the opposite charge to the argon ion, the ions are attracted to the target forming a thin and even (usually in the order of nanometers) coating on samples placed close to the anode. The process is usually performed in a partial vacuum container with a suitable gas environment. Carbon evaporation procedures are based in the controlled evaporation of a high purity carbon rod in a dedicated sample coater that deposits a thin even coat of carbon on the surface of non-metal samples, providing a uniform layer of carbon with a thickness (usually in the order of nanometers) according to the microscopic analysis to be performed. Metallic coating of the samples avoid charging the sample, reduce thermal damage, and improve secondary electron emission during scanning electron microscopy. Carbon coating is typically used for scanning and transmission electron microscopy examinations but may be used also for x-ray micro-analysis and other thin film applications.
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