Patent ID: 9747977
Date: 2017-08-29
CPC Classifications: G11C

Claim:
1. A method of verifying cell programming for phase change memory, comprising: sending a reset pulse to a phase change memory cell; sensing a first instance of a threshold voltage of the phase change memory cell in response to applying a first verify voltage across the phase change memory cell; sensing a second instance of the threshold voltage of the phase change memory cell in response to applying a second verify voltage across the phase change memory cell where the second verify voltage is lower than the first verify voltage; determining whether the first instance of the threshold voltage of the phase change memory cell was above the first verify voltage and the second instance of the threshold voltage of the phase change memory cell was below the second verify voltage; and determining that the phase change memory cell was disturbed by the first verify voltage if the first instance of the threshold voltage of the phase change memory was above the first verify voltage and the second instance of the threshold voltage of the phase change memory cell was below the second verify voltage.