Hetero-switching layer in a RRAM device and method

A method for writing to a resistive switching device, comprising:

• providing a plurality of resistive switching devices, wherein the plurality of resistive switching devices comprises a first plurality of electrodes, a plurality of switching material stacks, wherein each switching material stack comprises a first switching material and a second switching material, wherein the second switching material overlies the first plurality of electrodes, wherein the first switching material overlies the second switching material, wherein a second plurality of electrodes overlies the first switching material, wherein the second plurality of electrodes comprise at least a metal material, wherein the first switching material is characterized by a first switching voltage, wherein the second switching material is characterized by a second switching voltage, wherein the first switching voltage is characterized by a first amplitude, wherein the second switching device is characterized by a second amplitude, and wherein the first amplitude is greater than the second amplitude;
• and
• applying a first voltage across an electrode from the second plurality of electrodes and an electrode from the first plurality of electrodes thereby applying the first voltage across a switching material stack from the plurality of switching material stacks, wherein the first voltage is greater than a write voltage to thereby cause first resistive switching material of the switching material stack to change from a high resistance state to a low resistant state.

A method for reading from a resistive switching device, comprising:

• providing a plurality of resistive switching devices, wherein the plurality of resistive switching devices comprises a first plurality of electrodes, a plurality of switching material stacks, wherein each switching material stack comprises a first switching material and a second switching material, wherein the second switching material overlies the first plurality of electrodes, wherein the first switching material overlies the second switching material, wherein a second plurality of electrodes overlies the first switching material, wherein the second plurality of electrodes comprise at least a metal material, wherein the first switching material is characterized by a first switching voltage, wherein the second switching material is characterized by a second switching voltage, wherein the first switching voltage is characterized by a first amplitude, wherein the second switching device is characterized by a second amplitude, and wherein the first amplitude is greater than the second amplitude;
• and
• applying a first voltage across an electrode from the second plurality of electrodes and an electrode from the first plurality of electrodes thereby applying the first voltage across a switching material stack from the plurality of switching material stacks, wherein the first voltage is greater than the second switching voltage but lesser than a write voltage of the first switching material to thereby cause second resistive switching material of the switching material stack to change from a high resistance state to a low resistance state.