Methods For Writing To An Array Of Resistive Random Access Memory Cells
Numerous embodiments of methods for writing to a resistive random access memory (RRAM) cell are disclosed. In one embodiment, the system verifies if a current through the RRAM cell exceeds a threshold value, and if it does not, the system executes a concurrent write-while-verify operation. In another embodiment, the system verifies if current through the RRAM cell has reached a target value, and if it has not, the system executes a write operation and then verifies the write operation using a current comparison.
1 . A method of writing to a resistive random access memory (RRAM) cell, comprising:
verifying if a current through the RRAM cell exceeds a threshold value; and
if the current does not exceed the threshold value, executing a concurrent write-while-verify operation to the RRAM cell.
2 . The method of claim 1 , wherein the verifying step comprises current comparison.
3 . The method of claim 2 , wherein the current comparison is a folded current comparison.
4 . The method of claim 1 , wherein the verifying step comprises voltage comparison.
5 . The method of claim 1 , wherein the verifying step comprises using a diode connected transistor connected to a bitline for performing a current comparison.
6 . The method of claim 1 , wherein the concurrent write-while-verify operation comprises incrementing a write current using coarse resolution and fine resolution controls.
7 . The method of claim 1 , wherein the concurrent write-while-verify operation comprises applying a fixed voltage.
8 . The method of claim 1 , wherein the concurrent write-while-verify operation comprises applying a ramping voltage.
9 . The method of claim 1 , wherein the concurrent write-while-verify operation comprises applying voltage in stepped increments.
10 . The method of claim 1 , wherein the concurrent write-while-verify operation comprises applying voltage in stepped decrements.
11 . The method of claim 1 , wherein the concurrent write-while-verify operation comprises applying voltage with a variable write pulse width.
12 . A method of writing to a resistive random access memory (RRAM) cell, comprising:
verifying if current through the RRAM cell has reached a target value; and
if the current through the RRAM cell has not reached a target value, executing a write operation to the RRAM cell and verifying the write operation using a current comparison.
13 . The method of claim 12 , wherein the current comparison is a folded current comparison.
14 . The method of claim 12 , wherein the step of verifying if current through the RRAM cell has reached a target value comprises using a diode connected transistor connected to a bitline for performing a current comparison.
15 . The method of claim 12 , wherein the executing step comprises incrementing a write current using coarse resolution and fine resolution controls.
16 . The method of claim 12 , wherein the write operation comprises applying a fixed voltage.
17 . The method of claim 12 , wherein the write operation comprises applying a ramping voltage.
18 . The method of claim 12 , wherein the write operation comprises applying voltage in stepped increments.
19 . The method of claim 12 , wherein the write operation comprises applying voltage in stepped decrements.
20 . The method of claim 12 , wherein the write operation comprises applying voltage with a variable write pulse width.
21 . The method of claim 12 , wherein the executing step utilizes hybrid control.
22 . The method of claim 21 , wherein the hybrid control comprises an internal control and an external control from a tester.