Compensation for threshold voltage variation of memory cell components
View Patent ↗Methods, systems, and devices for operating a ferroelectric memory cell or cells are described. Before reading a memory cell, the voltage on an access line of the memory cell may be initialized to a value associated with the threshold voltage of a switching component in electronic communication with the memory cell. The voltage may be initialized by reducing the existing voltage on the access line to the value. The switching component or an additional pull down device, or both, may be used to reduce the voltage of the access line. After the access line has been initialized to the value, the read operation may be triggered.
1. A method, comprising:
adjusting a voltage on an access line coupled with a memory cell and a capacitor to a threshold voltage of a switching component;
applying a voltage across the memory cell of a memory array;
charging the capacitor coupled with the memory cell based at least in part on the voltage across the memory cell, wherein charging the capacitor comprises activating the switching component coupled with the access line;
pulling, using the switching component, a current from the access line based at least in part on activating the switching component;
determining an amount of charge on the access line based at least in part on pulling the current from the access line, wherein determining the amount of charge on the access line is based at least in part on a number of times the switching component pulls a portion of the current from the access line; and
determining a logic state of the memory cell based at least in part on charging the capacitor and adjusting the voltage on the access line.
2. The method of claim 1 , wherein adjusting the voltage on the access line further comprises:
reducing the voltage on the access line coupled with the memory cell and the capacitor.
3. The method of claim 1 , wherein applying the voltage across the memory cell further comprises:
activating a selection component coupled with the capacitor and the memory cell.
4. The method of claim 1 , wherein determining the amount of charge on the access line is based at least in part on comparing the amount of charge on the access line to a reference charge.
5. The method of claim 1 , further comprising:
determining the logic state of the memory cell based at least in part on determining the amount of charge on the access line.
6. The method of claim 1 , further comprising:
determining an amount of time the switching component is active based at least in part on reducing the voltage on the access line coupled with the memory cell and the capacitor.
7. The method of claim 6 , further comprising:
determining the logic state of the memory cell based at least in part on determining the amount of time the switching component is active.
8. An electronic memory apparatus, comprising:
a memory cell;
a switching component in electronic communication with the memory cell through an access line; and
a controller in electronic communication with the memory cell and the switching component, wherein the controller is operable to:
adjust a voltage on the access line coupled with the memory cell and a capacitor to a threshold voltage of the switching component;
apply a voltage across the memory cell of a memory array;
charge the capacitor coupled with the memory cell based at least in part on the voltage across the memory cell;
activate the switching component to discharge an amount of charge from the memory cell for one or more segments of time based at least in part on adjusting the voltage on the access line; and
determine a logic state of the memory cell based at least in part on charging the capacitor and adjusting the voltage on the access line.
9. The electronic memory apparatus of claim 8 , wherein applying the voltage across the memory cell further comprises applying the voltage for a duration of time to increase the voltage on the access line above a threshold.
10. The electronic memory apparatus of claim 8 , wherein the controller is operable to:
activate the switching component coupled with the access line based at least in part on charging the capacitor; and
establish a conductive path between the memory cell and the capacitor based at least in part on activating the switching component.
11. The electronic memory apparatus of claim 8 , wherein the controller is operable to:
read the logic state after determining the logic state of the memory cell.