SEM is a kind of microscope to observe the topography of materials. SEM has some advantages: it has a large depth of field and we can observe the 3D image of the sample and analyzing its topography, its magnification range is widely and we could make sample easily because of the X-ray spectrometry, which can determine the elements of sample.
When electron beam attack the sample, incident electron will be diffracted and change the direction or even loose some energy. During this process, accumulating scattered angle of some incident electron is more than 90 degrees, they will re-emit from the surface of the sample. The characteristic of backscattered is high energy and close to the energy of incident electron, the resolution is low. On the contrary, the energy of secondary electrons is very small and less than 50eV, incident electrons and sample atoms can scatter several times which is limited. As a result, it does not spread to other direction. We can see the figure 1 to realize how they worked. When we get the image caused by backscattered, we can notice that the image is not very clear, and we can see some dark and light regions. That is, we can determine the ingredients of sample through this imaging strategy. The sample of secondary image will be very clear and we even can find out there are some hole or peak on it. That is, we can get the 3D image through secondary imaging and analyze the topography of the sample. …show more content…
It has several advantages: it has a high efficient to detect X-ray, EDS could calculate all of ingredients that locate in analyzing point and make results in few minutes. The structure is simple and stable. It does not have to focus to the sample and fits analyze rough surface of the
When electron beam attack the sample, incident electron will be diffracted and change the direction or even loose some energy. During this process, accumulating scattered angle of some incident electron is more than 90 degrees, they will re-emit from the surface of the sample. The characteristic of backscattered is high energy and close to the energy of incident electron, the resolution is low. On the contrary, the energy of secondary electrons is very small and less than 50eV, incident electrons and sample atoms can scatter several times which is limited. As a result, it does not spread to other direction. We can see the figure 1 to realize how they worked. When we get the image caused by backscattered, we can notice that the image is not very clear, and we can see some dark and light regions. That is, we can determine the ingredients of sample through this imaging strategy. The sample of secondary image will be very clear and we even can find out there are some hole or peak on it. That is, we can get the 3D image through secondary imaging and analyze the topography of the sample. …show more content…
It has several advantages: it has a high efficient to detect X-ray, EDS could calculate all of ingredients that locate in analyzing point and make results in few minutes. The structure is simple and stable. It does not have to focus to the sample and fits analyze rough surface of the