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Entire range of material, metals alloys, ceramics, polymers, composites, electronic as well as biological samples can be studied under various modes of operation of the microscope. But, sample preparation requirement for successful observations is rather stringent and varied depending on the material. The final cleaning of the sample involved organic solvents in many cases. This leaves a contaminant layer of about 5nm on top of the surface of the sample. This layer brings down the quality of images. For conventional imaging this is not deterrent to carrying on the investigation with a compromise on the quality of images. But, when one wants to do HRTEM using the best capability of the microscope and its best resolution, around 0.2nm, this layer becomes a deterrent as the sample thickness at which these studies can be carried out is about 10-20nm (ideal thickness). In this scenario, the contamination layer makes the analysis impossible. The plasma cleaning removes the contamination layer without any damage to the sample surface. This opens up additional scope of investigations and also enable the users to take the full advantage of the high resolution capability of the machine.Another utility of the system is in cleaning up the sample after studying the sample for a specific duration. An intermittent cleaning with plasma removes all contamination and the sample becomes fit again to carry out the studies to its completion.
Elemental analysis with the EDAX system is another situation wherein the plasma cleaning is of great importance. In carrying out the EDS analysis a focused probe of electrons irradiate a sample region of 10-20nm and analyses the X-ray signal generated. During this period of about 50-100 seconds of irradiation, the specific region gets a carbon contamination built up and imaging this area is not possible after EDS analysis. In this sort of situations the plasma cleaning of the sample completely removes the contamination only in about 10-15 minutes.
The Solarus plasma cleaning system that we have at EM facility, MSE has the provision for using it with a range of TEM models as well as for SEM stages. Plasma cleaning system will not only enhance the quality of work but also open up for the complete utilization the TEM capability
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