Electron holography study for two-dimensional dopant profile measurement with specimens prepared by backside ion milling.

The visualization of two-dimensional dopant profiles and the quantitative analysis of the built-in potential across the p-n junction, DeltaV(p-n), by electron holography were carried out with specimens prepared from the backside ion milling method combined with the focused ion beam technique. It was possible to obtain dopant profiling of the large field of view with low surface damage and gradually changed thickness. From the quantitative analysis using the phase information of electron holography and the thickness information of electron energy-loss spectroscopy, DeltaV(p-n) was estimated to be about 0.78 V assuming that the thickness of the dead layer on both surfaces is 50 nm, which is to show the difference of within 12% from the calculated value. It demonstrates that the backside ion milling method is a very promising specimen preparation technique for the reliable and quantitative analysis of dopant profiling with electron holography.