NOR flash memory programming method and device and NOR flash memory

Abstract

The invention provides a method and a device for programming an NOR flash memory and the NOR flash memory. The NOR flash memory comprises a memory unit. The method comprises the following steps: receiving a programming operation instruction, judging whether the threshold voltage of the memory unit to be programmed is smaller than a preset value or not, and if the threshold voltage is greater thanthe preset value, executing low-voltage programming operation on the memory unit to be programmed of which the threshold voltage is greater than the preset value. According to the invention, programming operation is executed; executing a low-voltage programming operation on the storage unit which is greater than a preset value. Therefore, the storage unit is not programmed to a very high thresholdvoltage after executing the programming operation; after the low-voltage programming operation, the threshold voltage of the storage unit is relatively more concentrated; and the threshold voltage ofthe memory unit after the low-voltage programming operation is lower than the threshold voltage of the memory unit after the normal programming operation, so that the erasure operation of the memoryunit after the low-voltage programming operation is faster than the erasure operation of the memory unit after the normal programming operation, and the programming performance and the erasure performance of the NOR flash memory are improved on the whole.

Description

technical field [0001] The invention relates to the storage field, in particular to a method and device for programming a NOR flash memory and the NOR flash memory. Background technique [0002] At present, when NOR flash memory performs programming operations, the same programming voltage is uniformly applied to different memory cells that need to be programmed to perform programming operations. For memory cells whose original threshold voltage is relatively high in the erasing threshold range, it is easy to be programmed. A very high threshold voltage may cause the threshold voltage distribution to overlap, resulting in programming data errors, and this part of the programmed memory cells will be erased relatively slowly when performing an erase operation. [0003] refer to figure 1 , shows a schematic diagram of the threshold voltage distribution principle of the 4-bit (bit) storage unit of the existing NOR flash memory when performing programming, wherein Vread1, Vread2...

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Problems solved by technology

[0004] A method and device for programming a NOR flash memory and a NOR flash memory provided by the present invention solve the problem that memory cells with relatively high threshold voltages will be programmed to very high threshold voltages due to the use of the same programming voltage to perform programming operations. Issues that lead to excessive dispersion of threshold voltages after programming

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