Posted by Dan (220.127.116.11) on January 31, 2007 at 13:11:03:
In Reply to: Can you profile a sheer cross section ? posted by Holin Chang on January 30, 2007 at 22:29:19:
: Can you profile a sheer cross section of the designated location? We like to know the doping profile of a device with multi layers of different doping in about 100um square. and the layers thickness is totally 100um. A beveling cross section is hard to cover all these layers.
Yes we can profile samples perpendicularly. But we usually don't like to. The problem is that we need to take a minimum step of 2um between probings to avoid the region damaged by the prior probing. Each measurement leaves a damaged region on the sample which would cause noise and inaccurate readings if landed on again. This means we can't measure a depth increment of less than 2um on a perpendicular plane. At best we would be able to provide 50 points for the entire 100um of depth you want measured. This may be adequate resolution for your sample but you mention multiple layers. We like to get at least 15-20 points per layer. So if your samples had more than 3 layers, we probably wouldn't have enough data to properly characterize your structure. We have a depth resolution calculator on our technical info page you may find useful.
: We can provide the sheer cross section sample.
We would probably have to repolish the sample's cross section in order to have an appropriate surface for our measurements. Most samples we receive with an existing cross section have been polished with a combination chemical/mechanical method which can cause false readings when measured with a spreading resistance probe. Or, enough time has passed for native oxide to grow thick enough to cause problems. We would not have to polish much, just enough to freshen up the surface.