Method for forming ReRAM chips operating at low operating temperatures
Forming a resistive memory structure at a temperature well above the operating temperature can reduce the forming voltage and create a defect distribution with higher stability and lower programming voltages. The forming temperature can be up to 200 C above the operating temperature. The memory chip can include an embedded heater in the chip package, allowing for a chip forming process after packaging.
1. A method comprising
forming a memory structure, wherein the memory structure comprises an insulator layer disposed between two electrode layers;
heating the memory structure to a temperature higher than an operating temperature of the memory structure;
applying a first voltage to the two electrode layers to form a switching layer from the insulator layer;
stopping heating the memory structure.
2. A method as in claim 1 wherein the operating temperature is less than 85° C., wherein the forming temperature is between 85° C. and 200° C.
3. A method as in claim 1 wherein heating the memory structure comprises applying a second voltage or current to a heater, wherein the heater is disposed in a vicinity of the memory structure.
4. A method as in claim 1 further comprising
monitoring the temperature of the memory structure after heating.
5. A method as in claim 1 wherein forming a switching layer from the insulator layer comprises forming a filament in the insulator layer.
6. A method comprising
forming a memory chip, wherein the memory chip comprises a memory structure, a heater element and a temperature sensor encapsulated in a chip package, wherein the memory structure comprises an insulator layer disposed between two electrode layers;
applying a first current to the heater element to heat the memory structure to a temperature higher than an operating temperature of the memory structure;
measuring a temperature of the temperature sensor;
applying a second voltage to the two electrode layers to form a switching layer from the insulator layer after the temperature reaches a setpoint temperature;
stopping applying the first current and the second voltage.
7. A method as in claim 6 wherein the memory structure is heated to 100° C. higher than the operating temperature of the memory structure.
8. A method as in claim 6 wherein the operating temperature is less than 85° C., wherein the memory structure is heated to a temperature less than 200° C.
9. A method as in claim 6 wherein heating the memory structure comprises applying a voltage or current to a heater, wherein the heater is disposed in a vicinity of the memory structure.
10. A method as in claim 6 further comprising
monitoring the temperature of the memory structure after heating.
11. A method as in claim 6 wherein forming a switching layer from the insulator layer comprises forming a filament in the insulator layer.
12. A method as in claim 6 wherein the memory structure comprises an array of memory devices, wherein a memory device comprises a switching element disposed between two electrode layers.
13. A method as in claim 12 wherein heating the memory structure comprises heating the array of memory devices.
14. A method as in claim 6 wherein the memory chip is encapsulated with external contact pins.
15. A method as in claim 14 wherein the first current or the second voltage is applied to the memory chip through the external contact pins.