Sample preparation technique for the revelation of a semiconductor dopant using an FE-SEM

It is challenging to obtain the dopant profile within semiconductor devices with sufficient contrast from FIB milled cross sections due to a damage layer being formed during the milling process. In order to obtain accurate and sufficient dopant profile information, we examined FIB processing conditions and Ar ion milling conditions using a standard sample. As a result, an accelerating voltage of 40 kV for FIB processing and an accelerating voltage of 0.5 kV in Ar ion milling is the most suitable combination for observing a dopant profile clearly. We also applied an optimized preparation protocol to a commercial NMOS sample to demonstrate dopant profile visualization.