Nonvolatile memory erase method and device

Abstract

The invention discloses a nonvolatile memory erase method and a nonvolatile memory erase device. The method comprises the steps that: a target erasing target is subjected to a preprogramming operation, wherein the preprogramming operation is that 0 is written into memory units of the target erase object; whether the preprogramming operation is successful is examined, wherein the examining is that whether currents of the memories in the target erase object processed through the preprogramming operation under a certain gate voltage are all smaller than a target current value which is a current value with current margin; if the preprogramming operation is successful, a next step is executed, and if not, the progress is turned back to the execution of the preprogramming operation; the target erase object is subjected to an erase operation, wherein the erase operation is that 1 is written into memory units of the target erase object; and the target erase object is subjected to an over-erase examine operation, wherein the over-erase examine operation is that threshold voltage of memory units in the target erase object is adjusted. With the method and device provided by the invention, nonvolatile memory erase speed can be improved, and memory performance can be improved.

Description

technical field [0001] The present application relates to the technical field of semiconductor memory, in particular to a method for erasing a nonvolatile memory, and an erasing device for a nonvolatile memory device. Background technique [0002] There are two basic storage units (cells) in the memory, erase (erase) cell and program (PGM, programming) cell, that is, "1" and "0", so there are two corresponding types of erase and program. The basic operation of a memory unit. Among them, the process of changing a "0" cell into a "1" cell is called erasing; the process of changing a "1" cell into a "0" cell is called programming. Erasing speed and programming speed are two important indicators to measure memory performance, and this application mainly involves erasing. [0003] In the prior art, memory erasing mechanisms such as figure 1 As shown, the principle is as follows: [0004] Step1: Perform Pre_PGM (pre-programming) operation on the target block (block) that needs...

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Problems solved by technology

[0008] First, because the reference PV state corresponds to a higher threshold, which means that the Pre_PGM time is longer, especially for those few cells located near the PV state, so this will affect the entire erasing speed;

[0009] Second, for those cells with a higher threshold, it may cause Over Program (over-programming), and when these over-programmed cells are erased, it will take more wasted time, which also affects the erase In addition to speed

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