Resistive devices and methods of operation thereof

1. A method of operating a resistive switching device, the method comprising:

applying a program stress to a two terminal resistive memory unit, the program stress being applied at a program voltage configured to change a state of the memory unit from a first state to a second state;

applying a verification/stabilization stress to the two terminal resistive memory unit, the verification/stabilization stress being applied at a verification/stabilization voltage; and

applying an erase stress to the two terminal resistive memory unit, the erase stress being applied at an erase voltage configured to change a state of the memory unit from the second state to the first state, wherein the verification/stabilization voltage is between the program voltage and the erase voltage.

2. The method of claim 1 , further comprising:

detecting the state of the two terminal resistive memory unit after applying the verification/stabilization stress; and

applying the program stress if the two terminal resistive memory unit is in the first state.

3. The method of claim 2 , further comprising:

repeating the steps of applying the verification stress and detecting the state until the two terminal resistive memory unit is in the second state after the detecting.

4. The method of claim 1 , further comprising:

applying a read stress to the two terminal resistive memory unit, the read stress being applied at a read voltage between the verification/stabilization voltage and the program voltage.

5. The method of claim 4 , wherein the read stress is applied after applying the program stress but before applying the verification/stabilization stress.

6. The method of claim 1 , wherein applying a verification/stabilization stress comprises applying only a single pulse.

7. The method of claim 1 , wherein applying a verification/stabilization stress comprises applying a single pulse multiple times.

8. The method of claim 1 , wherein the first state is a low resistance state and wherein the second state is a high resistance state.

9. The method of claim 1 , wherein the erase voltage is applied for a shorter time than the verification/stabilization voltage.

10. The method of claim 1 , wherein the verification stress is positive.

11. The method of claim 1 , wherein the verification stress is negative.

12. A method of operating a resistive switching device, the method comprising:

applying a program stress to a two terminal resistive memory unit, the program stress being applied at a program voltage configured to change a state of the memory unit from a first state to a second state;

after applying the program stress, applying a read stress to the two terminal resistive memory unit, the read stress being applied at a read voltage; and

after applying the read stress, applying a verification/stabilization stress to the two terminal resistive memory unit, the verification/stabilization stress being applied at a verification/stabilization voltage, wherein the verification/stabilization voltage is between the read voltage of the two terminal resistive memory unit and a erase voltage of the two terminal resistive memory unit.

13. The method of claim 12 , further comprising:

applying an erase stress to the two terminal resistive memory unit, the erase stress being applied at an erase voltage configured to change a state of the memory unit from the second state to the first state.

14. The method of claim 13 , wherein the erase voltage is applied for a shorter time than the verification/stabilization voltage.

15. The method of claim 12 , wherein applying a verification/stabilization stress comprises applying only a single pulse.

16. The method of claim 12 , wherein applying a verification/stabilization stress comprises applying a single pulse multiple times.

17. The method of claim 12 , wherein the two terminal resistive memory unit comprises an ionic memory.

18. The method of claim 17 , wherein the ionic memory comprises conductive bridging memory.

19. The method of claim 12 , wherein the two terminal resistive memory unit comprises a metal oxide memory.

20. The method of claim 12 , wherein the two terminal resistive memory unit comprises a phase change memory.

21. A semiconductor device comprising:

a memory cell array comprising an array of two terminal resistive memory units;

a program circuit configured to program the array of two terminal resistive memory units;

a verification/stabilization circuit configured to apply a verification/stabilization stress on a first memory unit of the memory cell array, the verification/stabilization stress being a voltage between a read voltage of a memory unit of the array of two terminal resistive memory units and a erase or a program voltage of a memory unit of the array of two terminal resistive memory units; and

a detection circuit configured to detect a state of the first memory unit.

22. The device of claim 21 , wherein the verification/stabilization stress being a voltage between a read voltage of a memory unit of the array of two terminal resistive memory units and a erase voltage of a memory unit of the array of two terminal resistive memory units.

23. The device of claim 21 , wherein the verification/stabilization stress being a voltage between a read voltage of a memory unit of the array of two terminal resistive memory units and a program voltage of a memory unit of the array of two terminal resistive memory units.

24. The device of claim 21 , wherein each memory unit of the array of two terminal resistive memory units comprises an ionic memory.

25. The device of claim 24 , wherein the ionic memory comprises conductive bridging memory.

26. The device of claim 21 , wherein each memory unit of the array of two terminal resistive memory units comprises a metal oxide memory.