Methods for programming 1-R resistive change element arrays
View Patent ↗Methods for reading and programming one or more resistive change elements within a 1-R resistive change element array are disclosed. These methods include using measurement and storage elements to measure the electrical response of one or more selected cells within an array and then comparing that stored electrical response to the electrical response of a reference element within the array to determine the resistive state of the one or more selected cells. These methods also include programming methods wherein selectable current limiting elements are used to permit or inhibit programming currents from flowing through selected and unselected cells, respectively. These methods further include programming methods that use specific biasing of array lines to provide sufficient programming currents through only selected cells.
1. A method for adjusting the resistive state of a single resistive change element within a resistive change element array, comprising:
providing a resistive change element array, said resistive change element array comprising:
a plurality of word lines;
a plurality of bit lines; and
a plurality of resistive change elements, wherein each resistive change element has a first terminal and a second terminal and wherein said first terminal of each resistive change element is in electrical communication with a word line and said second terminal of each resistive change element is in electrical communication with a bit line;
floating all of said bit lines and all of said word lines within said resistive change element array;
selecting one of said plurality of resistive change elements;
driving the bit line in electrical communication with said selected resistive change element to a preselected voltage;
driving the word line in electrical communication with said selected resistive change element to ground;
discharging said bit line in electrical communication with said selected resistive change element through said selected resistive change element to provide a programming current through said selected resistive change element;
wherein said programming current adjusts the electrical resistance of said selected resistive change element from a first resistive state to a second resistive state.
2. The method of claim 1 wherein said first resistive state is lower than said second resistive state.
3. The method of claim 1 wherein said first resistive state is higher than said second resistive state.
4. The method of claim 1 wherein said first resistive state corresponds to a first logic value and said second logic state corresponds to a second logic value.
5. The method of claim 1 wherein said current limiting path is sufficient to prevent a discharge current through an unselected resistive change element from being large enough to adjust the resistive state of said unselected resistive change element.
6. The method of claim 1 wherein said resistive change elements are two-terminal nanotube switching elements.
7. The method of claim 6 wherein said two-terminal nanotube switching elements comprise a nanotube fabric.
8. The method of claim 1 wherein said resistive change elements are metal oxide memory elements.
9. The method of claim 1 wherein said resistive change elements are phase change memory elements.
10. The method of claim 1 wherein said resistive change element array is a memory array.