Study of redox reactions in resistive switching processes of AlOx/WOy based bilayer RRAM

Pulsed programming measurements were carried out to study the abrupt differences between the SET/RESET processes of the AlO
x
/WO
y
bilayer RRAM devices. Electrical measurement results showed that both SET and RESET switching are affected by the applied pulse amplitude. But the RESET operation has a strong relation with the pulse width. Calculation results indicate the RESET step needs more energy than the SET step. A combination of electrical field and joule heating is needed to complete the RESET step. A redox reaction model is proposed to explain the asymmetry characteristic of the SET/RESET operations.