Using the X-ray analysis in the SEM, like we did for the LED, we tried to examine what the SAW device was made of. We first looked at the metal around the outside of the device, and then the substrate in the middle, and the results are shown below.
The graph above is from the X-ray analysis of the metal round the outside, and appears to contain Oxygen, Aluminium, Silicon and Tantalum. However the main peak for silicon shown also contains one of the characteristic peaks for Aluminium. Because of this we were not totally sure whether it contains Silicon or not, but fairly certain about the other 3 elements. We used computer software to generate a graph of what a material under the same conditions would give under X-ray analysis, if it contained Silicon, and then if it did not. This confirmed that Silicon was present, as the peak labeled as Silicon was absent when we generated a graph of the material without silicon, confirming it was not just another Tantulum peak.
The analysis for the substrate showed very similar results, containing the same peaks as before but the dilemma about Silicon is still present, but our test on the other part of the substrate suggests that it will contain Silicon aswell. Therefore we expect it to have a similar composition to the rest of the SAW device, but in different concentrations.