The Impact of RTN Signal on Array Level Resistance Fluctuation of Resistive Random Access Memory

Read error caused by resistance change or fluctuation occurred in read operation is a critical issue of resistive random access memory (RRAM) and needs to be paid special attention in chip design. In this letter, we investigated the resistance fluctuation of an RRAM device fabricated on 28-nm CMOS platform, with statistical data collected on the sub-array of 1-Mb macro. The evolution of resistance states in various resistance ranges was traced under continuous read pulse with varied heights. The resistance states were found either randomly fluctuated or degraded over several orders of magnitudes, depending on the read voltage. The random telegraph noise measurement shows electron capture and emission at trap sites near or inside of the filament path acts as the major cause of resistance fluctuation, whereas atomic defects generation in the current transport path as the read voltage higher than 0.7-V results in large range variation. The results of this work provide a valuable guideline to reduce the bit error rate of RRAM chip.