Patent ID: 6909632

Claim:
A method comprising: providing a first layer of conductive array lines, the conductive array lines being arranged so that they do not come into direct contact with each other; providing a second layer of conductive array lines, the conductive array lines being arranged so that they do not come into direct contact with either each other or any of the conductive array lines of the first layer; selecting at least one conductive array line pair, the conductive array line pair being one of the conductive array lines from the first layer and one of the conductive array lines of the second layer; applying a read voltage across the at least one conductive array line pair during a read mode, the read voltage producing a read current, wherein the read current is indicative of a first program state when the read current is at a first level and indicative of a second program state when the read current is at a second level, the read current being ineffective to produce a change in program state; applying a first voltage pulse across the least one conductive array line pair during a first write mode if in the second program state, wherein the first voltage pulse is effective to modify the programming state from the second program state to the first program state; and applying a second voltage pulse across the least one conductive array line pair during a second write mode if in the first program state, wherein the second voltage pulse is effective to modify the programming state from the first program state to the second program state.