Large resistive-switching phenomena observed in Ag/Si₃N ₄/Al memory cells

An effective resistive-switching effect has been observed in silicon nitride (Si₃N₄) dielectrics in Ag/Si₃N ₄/Al memory cells. The ratio of the low resistance to high resistance state was larger than 10⁷ at 1.2 V for a 10 nm thick Si ₃N₄ layer. This switching behavior is attributed to a change in the conductivity of the Si₃N₄ dielectrics, depending on whether nitride-related traps are filled with electrons under positive biases or unfilled under negative biases. This assertion is experimentally confirmed from the relationship between the amount of charges trapped in the Si₃N₄ layer and the corresponding changes in its resistance with respect to bias voltages. In addition, the formation or dissolution of the conductive path is confirmed by conductive atomic force microscopy current images.