Scanning electron beams provide a superior method of failure analysis by observing the voltage contrast (VC) both in frontend and back-end processes. Back-end VC tells us both metal/via open/short issues. Front-end VC tells us not only open/short issue but also additional doping information. A case on the application of passive voltage contrast (PVC) on doping information was studied. This paper explains the mechanism producing passive voltage contrast and describes three methods of sample preparation and provides examples of the results achieved.