Voltage management for improved tRP timing for FeRAM devices

Patent metadata

Field	Value
Publication number	US-12293783-B2
Application number	US-202217829054-A
Country	US
Kind code	B2
Filing date	May 31, 2022
Priority date	May 31, 2022
Publication date	May 6, 2025
Grant date	May 6, 2025

Abstract

Systems and methods related to a memory device that includes a command interface configured to receive read commands and write commands to invoke read and write operations. The memory device also includes a memory bank having multiple memory cells implemented using ferroelectric layers between plate lines and digit lines. The memory device also includes bank control circuitry configured to control operation of the memory bank. The operation of the memory bank includes programming both high and low logic values as a write back to the multiple memory cells during a read and write phase where the read and write operations are performed after sensing values from the multiple memory cells.

First claim

The invention claimed is:

1. A memory device, comprising:
a command interface configured to receive read commands and write commands to invoke read and write operations;
a memory bank comprising a plurality of memory cells implemented using ferroelectric layers between plate lines and digit lines; and
bank control circuitry configured to control operation of the memory bank, wherein the operation of the memory bank comprises programming both high and low logic values as a write back to the plurality of memory cells during a read and write phase where the read and write operations are performed after sensing values from the plurality of memory cells, wherein a plate voltage of a plate line of the plate lines is maintained at a constant voltage from the sensing through programming both the high and low logic values in a same period with a constant voltage of a wordline by swinging the digit lines alternatingly between a maximum voltage and a minimum voltage during the same period, wherein the constant voltage is between the maximum voltage and the minimum voltage of the digit lines during the programming of the high and low logic values.

2. The memory device of claim 1 , wherein the memory bank comprises:
a plurality of plate lines each corresponding to two memory cells; and
a plurality of digit lines each corresponding to a respective memory cell.

3. The memory device of claim 2 , wherein each bit of data to be stored in the memory bank is stored as complementary data in two different memory cells.

4. The memory device of claim 2 , wherein each bit of data to be stored in the memory bank is stored in a single memory cell.

5. The memory device of claim 1 , wherein the constant voltage is a nominal voltage for ferroelectric-based memory cells.

6. The memory device of claim 1 , wherein the bank control circuitry is configured to receive a write command from the command interface during the read and write phase and programming a corresponding memory cell of the plurality of memory cells with a value from the write command during the read and write phase.

7. The memory device of claim 1 , comprising a plurality of sense amplifiers configured to sense stored charges of the memory cells during a tRCD phase that has a defined duration to open a cell and the sensing occurs at the end of the tRCD phase.

8. The memory device of claim 7 , wherein the voltage of the plate line and the voltage of a wordline both increase during the tRCD phase to levels that are constant through the read and write phase.

9. The memory device of claim 8 , wherein a tRP phase occurs after the read and write phase, the tRP phase has a defined duration to close a page of memory, and no programming of high or low logic values is performed during the tRP phase.

10. The memory device of claim 9 , wherein the voltage of the wordline and the voltage of the plate line decrease to idle values during the tRP phase.

11. The memory device of claim 1 , wherein the maximum voltage of the digit lines during the programming of the high and low logic values is 3.0V, the minimum voltage for the digit lines during the programming of the high and low logic values is 0V, and the constant voltage is 1.5V.

12. The memory device of claim 1 , wherein a plurality of digit lines of the digit lines is used to perform reprogramming using a single plate line.

13. The memory device of claim 11 , wherein the constant voltage of the wordline during the same period is 4.7V.

14. A memory device, comprising:
a plate line;
a ferroelectric layer implementing a memory cell and coupled to the plate line;
digit lines coupled to the ferroelectric layer;
a sense amplifier coupled to the digit lines and configured to sense and amplify a voltage received at the digit lines from the memory cell; and
bank control circuitry configured to program a logic high value back to the memory cell after sensing the voltage in the sense amplifier and to program a logic low value back to memory cell after sensing a low value in the sense amplifier, wherein writing back the logic high value or the logic low value occurs while reading and writing operations are performed during a read and write phase of operation, wherein a plate voltage of the plate line is maintained at a constant voltage from the sensing through programming both the logic high and logic low values to corresponding memory cells in a same period with a constant voltage of a wordline by swinging the digit lines alternatingly between a maximum voltage and minimum voltage during the same period, wherein the constant voltage is between the maximum voltage and the minimum voltage of the digit lines during the programming of the logic high and logic low values.

15. The memory device of claim 14 , wherein the bank control circuitry is configured to maintain the voltage of the plate line at a nominal voltage during the read and write phase.

16. The memory device of claim 14 , wherein the maximum voltage of the digit lines during the programming of the high and low logic values is 3.0V, the minimum voltage for the digit lines during the programming of the high and low logic values is 0V, and the constant voltage is 1.5V.

17. The memory device of claim 14 , wherein a plurality of digit lines of the digit lines is used to perform reprogramming using a single plate line.

18. The memory device of claim 16 , wherein the constant voltage of the wordline during the same period is 4.7V.

19. A method comprising:
sensing a stored value stored in a ferroelectric memory cell of a memory device using a sense amplifier; and
programming the memory cell to a logic high value during a read and write phase where read and write operations are being performed for the memory device,
programming a logic low value to the memory cell during the read and write phase, wherein programming the memory cells comprises maintaining a plate voltage of a plate line at a constant voltage from a sensing phase through programming both the logic high value and the logic low value in a same period with a constant voltage of a wordline by swinging digit lines alternatingly between a maximum voltage and a minimum voltage during the same period, wherein the constant voltage is between the maximum voltage and the minimum voltage of the digit lines during the programming of the logic high value and logic low value.

20. The method of claim 19 , wherein the maximum voltage of the digit lines during the programming of the high logic value and the low logic values is 3.0 V, the minimum voltage for the digit lines during the programming the high logic value and the low logic values is 0V, and the constant voltage is 1.5V.

21. The method of claim 19 , wherein programming the logic low value and programming the logic high value for multiple digit lines including the digit lines comprises utilizes the plate line as a single plate line.

22. The method of claim 20 , wherein the constant voltage of the wordline during the same period is 4.7V.

Assignees

• Micron Technology Inc

Inventors

• Vimercati Daniele
• Mazzeo Giovanni

Classifications

• G11C11/221

  using ferroelectric capacitors · CPC title

• G11C11/2275

  Writing or programming circuits or methods · CPC title

• G11C11/2273

  Reading or sensing circuits or methods · CPC title

• G11C11/2253

  Address circuits or decoders · CPC title

• G11C11/2297

  Power supply circuits · CPC title