Patent ID: 8101937

Claim:
A multistate nonvolatile memory element comprising: a first resistive switching layer, which comprises titanium oxide, having a first low resistive state and a first high resistive state; a second resistive switching layer, which comprises doped nickel oxide, is connected in series with the first resistive switching layer, the second resistive layer having a second low resistive state and a second high resistive state; and a third resistive switching layer, which comprises nickel oxide, is connected in series with the first resistive switching layer and the second switching layer, the third resistive switching layer having a third low resistive state and a third high resistive state, wherein the first resistive switching layer, the second resistive switching layer and the third resistive switching layer exhibit four stable states depending upon a resistance of each layer of said first resistive switching layer, the second resistive switching layer and the third resistive switching layer and allows storage of two bits within the first resistive switching layer, the second resistive switching layer and the third resistive switching layer.