Electronic device and method of operating memory cell in the electronic device

A method of manufacturing an electronic device including memory cells, the method comprising:

• forming memory cells, each of the memory cells including a variable resistance layer in an amorphous state regardless of a value of data stored in the memory cell;
• measuring threshold voltages of the memory cells;
• and
• setting a sub-threshold voltage to be lower than a lowest threshold voltage among the threshold voltages of the memory cells,
• wherein a reset operation of programming a selected memory cell among the memory cells to a high-resistance amorphous state is performed by applying the sub-threshold voltage to the selected memory cell without another voltage applying operation.