Method for adjusting a resistive change element using a reference
View Patent ↗A method of adjusting a resistive change element using a reference is disclosed. The method comprises inspecting a resistive change element to determine a first state; comparing the first state to a reference wherein said reference provides stimulus parameters corresponding to a transition from the first state to a second state; and applying the stimulus parameters to the resistive change element. A resistive change memory cell array is also disclosed.
1. A method of adjusting the resistance of a non-volatile resistive change element from a first state to a desired second state, comprising:
inspecting a resistive change element to determine a first state;
determining if said first state is distinct from a desired second state;
selecting a set of stimulus parameters from a pre-generated list of stimulus parameter sets, wherein said selected set of stimulus parameters are selected in response to said determined first state and said desired second state and correspond to a transition from said determined first state to said desired second state, when said determined first state is distinct from said desired second state; and
applying said selected set of stimulus parameters to said resistive change element, when said determined first state is distinct from said desired second state.
2. The method of claim 1 wherein said step of inspecting comprises applying a test voltage to said resistive change element and measuring a resulting current through said resistive change element.
3. The method of claim 2 wherein said resulting current is measured using an ammeter in series with said resistive change element.
4. The method of claim 2 wherein said test voltage is provided by a voltage source.
5. The method of claim 4 wherein said resulting current is measured by monitoring the current supplied by said voltage source.
6. The method of claim 4 wherein said voltage source is a programmable power supply.
7. The method of claim 4 wherein said voltage source is a sense amplifier.
8. The method of claim 1 wherein said step of inspecting comprises supplying a test current to said resistive change element and measuring a resulting voltage across said resistive change element.
9. The method of claim 8 wherein said resulting voltage is measured using a voltmeter across said resistive change element.
10. The method of claim 8 wherein said test current is supplied by a current source.
11. The method of claim 10 wherein said resulting voltage is measured by monitoring the voltage supplied by said current source.
12. The method of claim 10 wherein said current source is a programmable power supply.
13. The method of claim 10 wherein said current source is a sense amplifier.
14. The method of claim 1 wherein said pre-generated list of stimulus parameter sets includes a plurality of resistance value ranges.
15. The method of claim 1 wherein said pre-generated list of stimulus parameter sets includes a plurality of voltage value ranges.
16. The method of claim 1 wherein said pre-generated list of stimulus parameter sets includes a plurality of current value ranges.
17. The method of claim 1 wherein said selected set of stimulus parameters includes at least one of voltage level, pulse width, rise time, fall time, series resistance, and supply current.
18. The method of claim 1 wherein external environmental conditions are used to select said set of stimulus parameters from said pre-generated list of stimulus parameter sets.
19. The method of claim 18 wherein said external environmental conditions include at least one of temperature, humidity, air pressure, air quality, radiation levels, and stress.
20. The method of claim 1 wherein at least one of said steps of inspecting, determining, selecting, and applying is performed via a software program.
21. The method of claim 20 wherein said software program is executed on a personal computer.
22. The method of claim 20 wherein said software program is executed on a processing element in electrical communication with said resistive change element.
23. The method of claim 1 wherein at least one of said steps of inspecting, determining, selecting, and applying is performed via an electrical circuit.
24. The method of claim 23 where said electrical circuit includes at least one of a microprocessor, an FPGA, a CPLD, or a microcontroller.
25. The method of claim 23 wherein said electrical circuit includes analog power supply.
26. The method of claim 1 wherein said step of applying said selected set of stimulus parameters to said resistive change element adjusts the state of said resistive change element from a high resistive state to a low resistive state.
27. The method of claim 1 wherein said step of applying said selected set of stimulus parameters to said resistive change element adjusts the state of said resistive change element from a low resistive state to a high resistive state.
28. The method of claim 1 wherein said step of applying said selected set of stimulus parameters to said resistive change element adjusts the state of said resistive change element from one predefined resistive range to one of at least two other predefined resistance ranges.
29. The method of claim 1 wherein said selected set of stimulus parameters are applied to said resistive change element once.
30. The method of claim 1 wherein at least one of said steps of inspecting, determining, selecting, and applying is repeated at least once.
31. The method of claim 1 wherein said resistive change element is a two terminal nanotube switching element.
32. The method of claim 1 wherein said resistive change element is a metal oxide memory cell.
33. The method of claim 1 wherein said resistive change element is a phase change memory cell.
34. The method of claim 1 wherein said pre-generated list of stimulus parameter sets is a look up table.
35. The method of claim 1 wherein said pre-generated list of stimulus parameter sets is generated through a characterizing process performed on an array of resistive change memory elements.