Phase-change random access memory (PCRAM) cells have been studied extensively using electrical characterization and rather limited by detailed structure characterization. The combination of these two characterization techniques has hardly been exploited and it is the focus of the present work. Particularly, for improving the reliability of PCRAM such combined studies can be considered indispensable. Here, we show results for PCRAM line cells after series of voltage pulses with increasing magnitude are applied, leading to the first minimum sized amorphous mark, maximum amorphous resistance and over-programming, respectively. Furthermore, the crucial effect of electromigration limiting the endurance (cyclability) of the cells is demonstrated.