Method and device for restoring threshold voltage of memory

Abstract

The invention discloses a recovery method and device for threshold voltage of a memory. The method comprises the steps that at least one set of memory cells included in a memory are subjected to readrecovery operation in sequence, first voltage is applied to grid electrodes of the memory cells, second voltage is applied to grid electrodes of reference memory cells, drain electrodes of the reference memory cells are connected with a first end of a reference current source, and a second end of the reference current source is grounded; recovery verification operation is performed on the memory cell in the programming state in the recovery read operation, a first voltage is applied to the grid electrode of the memory cell in the programming state, and a first voltage is applied to the grid electrode of the reference memory cell; And programming operation is performed on the memory cell in the erased state in the recovery verification operation. According to the technical scheme provided by the embodiment of the invention, the current generated by the reference current source is increased for the current between the drain electrode and the source electrode of the reference storage unitthrough the reference current source, so that the transconductance influence caused by voltage change is eliminated, and the recovery operation time is shortened.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of nonvolatile memory, and in particular, to a method and device for restoring a threshold voltage of a memory. Background technique [0002] The memory cells in the programming state are stored for too long, and there is a case of electron loss. When the electron loss reaches a certain level, the threshold voltage of the memory cell in the programming state will be reduced to a certain value, and it is in a weak programming state. [0003] The first solution in the prior art is to perform a recovery read operation (recovery read) and a recovery verification operation (recovery verify) on a memory cell in a weakly programmed state, wherein the recovery read operation is performed on the gate of the memory cell and the reference memory cell. The voltage applied to the pole is the same as the normal read voltage. When the verification operation is resumed, the voltage applied to the gate...

AI Technical Summary

Problems solved by technology

[0005] In view of this, an embodiment of the present invention provides a method and device for restoring the threshold voltage of a memory, which solves the problem of the gate between the storage unit and the reference storage unit during the restoration of the read operation and the restoration of the verification operation in the prior art. The voltage switching time is too long and the read error is prone to occur when the read operation is resumed, so as to achieve the purpose of raising the threshold voltage of the memory cell in the weakly programmed state to the programmed state

Images