Patent ID: 7440315
Filing Date: 2008-10-21
Classification: G11C

Abstract:
1. A method for resetting a phase change memory cell having a memory cell threshold voltage, the memory cell threshold voltage being a voltage at which at least a portion of the amorphous phase change material of the memory cell starts to break down, the memory cell coupled to an access device having an access device threshold voltage, comprising: selecting a voltage V reading a resistance of the memory cell by (a) applying a voltage, smaller than the memory cell threshold voltage, to a bit line coupled to the memory cell, and by (b) applying a voltage, larger than the access device threshold voltage, to a word line coupled to the access device; if the resistance is larger than a chosen resistance, end the resetting of the memory cell; if the resistance is not larger than the chosen resistance, then proceed by: reading the resistance of the memory cell by (a) applying a voltage, smaller than the memory cell threshold voltage, to the bit line coupled to the memory cell, and by (b) applying a voltage, larger than the access device threshold voltage, to the word line; if the resistance is larger than the chosen resistance, end the resetting of the memory cell; if the resistance is not larger than the chosen resistance, then proceed by: return to the second reading step.