X-Rays and Another Method of Determining Film Thickness

Still about a week behind. Sorry. Though, I have been working :-) I had to set up my new website for the school I am moving to. And learned how to use Picasa for the pictures I am using on the blogger. Also found the site for the software we use to analyze the wrinkles, its free. Anyways, let me continue on the blog.

Today, we will use the X'Pert to detemine the thinkness of more film samples that we set up. We followed the same procedures as before: set up the spin coater, prepared the slide by cleaning with acetone, set up the correct speed for the spin coater, applied solution and started spin coater, if the film looks good, take to X'Pert room. Jiangshui allowed us to try it on our own, with him watching us. I really feel like a scientist at these times. We each tried it. We started up the X'Pert, put in the required settings for thickness analysis, set up the required componts, started X'Pert to detemine the "blank" and correct peak settings, placed slide in the X'Pert, set to required count rate and began analysis. Will take 1.5 hours so we went to explore another method of determing film thickness.

The other method requires a Profilometer and a cut on the film. This device actually places a very small needle, the stylus, on the surface of the film. The needle moves across the surface and then drops into the cut and then comes back up. By analyzing the readings from the normal surface height and the height of the cut, the computer can determine the thickness of the film.



This is a great device for deteming thickness since it is very easy to use. The only problem is that the film must be at least 1 micron or micrometer ( mm) and our films are ~90 nm which is ten times smaller than what can be used by the Profilometer. Because of this limitation we can't use it on the films we are working on so we made an extra one but it was made by dissolving a styrofoam cup in toluene. We let it dissolve for about an hour while we were doing the x-ray reflctivity and then did the spin coating with it. After setting up the profilometer and adjusting the stylus (see picture above). We started the device and collected the data. The data must be standardized and then the comparison is done. The film was about 1.36 microns ( mm) .

Even though we will not be using the profilometer, it was an experience to work with it. Remember it is called the Research Experience for Teachers so we are learning and experiencing all we can in the lab. Later on we will get to see how a scanning electron microscope works and other instruments along the way. We went back to the X'Pert and looked at our data on the computer and calculated the thickness to be 93.478 nm.