Posted by Dan (188.8.131.52) on March 06, 2009 at 18:16:29:
In Reply to: Angle Polishing posted by Sangwook Wee on March 05, 2009 at 21:14:54:
: I hope to polish a sample to measure a doping profile and damage depth of silicon wafer.
: How can I polish this sample?
: I heard that Normal polisher is difficult to do.
: Please, let me know.
All SRA samples requiring depth profiling are beveled at an angle less than perpendicular to spread the depth of interest into a distance across the surface. While there are many ways of doing this we've found the best way is to use a piston/collar jig that holds the sample against a diamond coated glass plate while the plate rotates.
There are many different polishing machines available but if your company has a surface science lab they may already have a setup that will work for you. Or, we can do your cross sections for you.
We started with commercially available fixed speed polishers and upgraded them with variable speed DC motors and gear reduction to slow the rotation way down. We did this because the polishing we do involves the finest grits of diamond available and high speeds cause the samples to hydroplane which a: reduces the actual cutting and b: allows larger debris to rotate back under the polishing area and cause scratches which can ruin the surface to be tested. And with some of our shallowest angles, a mere minute or two of one degree, a single rotation of the polishing wheel can remove all the material required to reach a particular location.
Since we require final roughness of 4-8 angstrom RMS and precision control of bevel start position, rounding, direction and angle, we designed and built our own piston and collar beveling jigs that are similar to those you can purchase from SSM in Pennsylvania. At least I believe you can still purchase them. If not, there are a variety of sample holders that can do the trick available from other companies. It will depend on your requirements as to which ones would work for you.