This paper demonstrates the methodology to understand the random dopant fluctuation (RDF) from the electrical measurements. The theoretical basis from an experimental discrete dopant profiling technique has first been introduced to analyze the RDF effect. It was further demonstrated on the advanced strain-silicon devices and advanced trigate devices. The discrete dopant distributions along the channel direction can be achieved, followed by the demonstration of the dopant fluctuation in SiC S/D strained and SiGe S/D strained nMOSFETs and pMOSFETs respectively. The carbon or Ge outdiffusion can be easily detected by this method. Finally, experiments have been extended to the advanced bulk-trigate CMOS devices. The sidewall corner effect in trigate has also been studied. It reveals that the corner effect is very challenging for the manufacturing. This approach provides a simple way to monitor the random dopant fluctuation as well as for the quality monitoring of future generation trigate devices.