Weak erase prior to read

摘要

Techniques are disclosed for accurately sensing memory cells without having to wait for a voltage that creeps up on word line after a sensing operation to die down. The word line creep up could cause electrons to trap in shallow interface traps of a memory cell, hence impacting its threshold voltage. In one aspect, trapped electrons are removed (e.g., de-trapped) from shallow interface traps of a memory cell using a weak erase operation. Therefore, problems associated with word line voltage creep up are reduced or prevented. Thus, the memory cell can be sensed without waiting, while still providing an accurate result. The weak erase could be part of a sensing operation, but that is not required. For example, the weak erase could be incorporated into the beginning part of a read operation, which provides for a very efficient solution.

主权项

1. A non-volatile storage device comprising:
a string of non-volatile storage elements; and a control circuit in communication with the string, the control circuit configured to:
sense a first non-volatile storage element on the string of non-volatile storage elements, sensing the first non-volatile storage element results in a threshold voltage of a second non-volatile storage element on the string changing from a first threshold voltage to a second threshold voltage;perform a weak erase of the second non-volatile storage element on the string to change the threshold voltage of the second non-volatile storage element back to substantially the first threshold voltage; andsense the second non-volatile storage element after performing the weak erase of the second non-volatile storage element at a time when the second non-volatile storage element still has substantially the first threshold voltage.