Patent ID: 7646633
Filing Date: 2010-01-12
Classification: G11C

Abstract:
1. A programming method of a phase-change memory having a phase-change element that transitions between a reset state corresponding to an amorphous state and a set state corresponding to a crystalline state, said method comprising: when said phase-change element is to be caused to transition to said reset state, applying to said phase-change element a first pulse having a first voltage that is a voltage higher than a threshold voltage for causing threshold switching in said phase-change element in said reset state, and moreover, that is a voltage that can cause a current to flow that corresponds to an amount of generated heat necessary for placing said phase-change element in said reset state; and when said phase-change element is to be caused to transition to said set state, applying to said phase-change element a second pulse having a second voltage that is higher than said threshold voltage but lower than said first voltage, and moreover, that is a voltage that only causes current to flow that cannot attain said necessary amount of generated heat, wherein the time width of said first pulse is equal to the time width of said second pulse.