Patent ID: 9177643
Filing Date: 2015-11-03
Classification: G11C

Abstract:
1. A multi-level programming method of a phase-change memory device, the multi-level programming method comprising: selecting a word line, where data are to be input, from multiple word lines; applying multiple bits of data to a bit line of a cell connected to the selected word line; applying a program current to the selected word line for programming of first data; applying a program current to the selected word line and applying a multi-level program current lower than the program current to one of word lines adjacent to the selected word line for programming of second data; and applying a program current to the selected word line and applying a multi-level program current lower than the program current to two of the word lines adjacent to the selected word line for programming of third data, wherein an ambient temperature of the cell is increased by the multi-level program current and a program volume of a phase-change material layer of the cell is reduced as the ambient temperature is increased, such that a program state of the cell is classified based on the program volume of the phase-change material layer of the cell.