The three-dimensional device simulation has become a necessary tool for the design and investigation of complex device structures. The evolution of the three-dimensional simulation tools is directly linked to the scaling of the devices and the increasing complex- ity of dynamic random access memory (DRAM) cells. Scaling of MOSFET devices led to a three-dimensional geometry with effects which cannot be handled by two-dimensional simulations anymore. With increasing integration density in DRAMs the third dimen- sion had to be utilized to realize the storage capacitor. The result- ing leakage...