Transient phase change effect in phase change memory devices

phase change memory;Phase change random access memory (PCRAM);transient effect;time-resolved;filament

Yeo, Eng Guan

关键词: phase change memory;    Phase change random access memory (PCRAM);    transient effect;    time-resolved;    filament;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/18640/Yeo_EngGuan.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Phase change random access memory (PCRAM) is a leading contender for next generation nonvolatilememory. The phase change mechanism from high resistance amorphous phase to lowresistance crystalline phase in nano-timescale is the most important characteristic of thesematerials. However, full understanding of the mechanism is still not achieved.Two time parameters were identified from the transient waveform, namely the delay and currentrecovery times. The link between crystallization kinetics and the transient phase change effectwas established by associating nucleation with delay time and growth with current recovery time.Real-time crystallization characterization was achieved.Parasitic capacitance had strong implications on the programming performance of PCRAM.Larger parasitic capacitance results in a larger leakage current, and hence higher applied voltagefor RESET operation needs to be applied. The larger parasitic capacitance also results in anincreased quenching time due to a longer voltage fall time, which results in a partiallycrystallized amorphous state.Continuing work is studying the effect of filament formation on phase change. Filamentformation is linked to the actual operating performance of the PCRAM device. This link isimportant in understanding how phase change occurs electrically and whether filament formationhas any effect on scaling of PCRAM devices.