Current continuity based 3D modeling of STM carrier profiling of semiconductor devices is achieved for the first time. Tunnel currents between probe tip and devices are solved consistently with current continuity consideration. It is revealed that tunnel current is reduced in current continuity model under depletion conditions. Spatial resolution achieved in the model is discussed in comparison to potential based modeling. Influence of discrete dopants is also discussed in concern with Coulomb potential fluctuations in nanoscale systems, which is a key issue of nano devices. © 2011 IEEE.