Semiconductor integrated circuit system and method for driving the same
A semiconductor integrated circuit system includes a phase-change line including a first phase-change area constituting a first memory cell and a second phase-change area constituting a second memory cell, a write current providing unit configured to phase-change a selected one of the first and second phase-change areas, and a phase-change compensation unit configured to restore the other of the first and second phase-change areas by compensating for a dummy phase-change caused in the other phase-change area due to a phase-change of the selected phase-change area.
1. A semiconductor integrated circuit system, comprising:
a memory cell array including a plurality of word lines, a plurality of bit lines crossing the plurality of word lines, and a phase-change memory cell formed on each of intersections of the plurality of word lines and the plurality of bit lines;
a reset current unit configured to apply a reset current to a bit line of the bit lines to control one selected from among the phase-change memory cells to have a amorphous state;
a set current unit configured to apply a set current to a bit line of the bit lines to control one selected from the phase-change memory cells to have a crystalline state; and
a phase-change compensation unit configured to apply a correction current to a memory cell adjacent to each of the selected phase-change memory cells through a word line of the adjacent memory cell to compensate for a phase-change of the adjacent memory cell.
2. The semiconductor integrated circuit system of claim 1 , wherein the correction current has a smaller magnitude than the set current and the reset current.
3. The semiconductor integrated circuit system of claim 1 , wherein the correction current has a magnitude for compensating for a phase-change of the adjacent memory cell without affecting phase-changes of memory cells adjacent to the adjacent memory cell.
4. The semiconductor integrated circuit system of claim 1 , wherein the correction current is applied as a signal pulsed at least once in a write enable period of the selected memory cell.
5. The semiconductor integrated circuit system of claim 1 , wherein the correction current is applied as a signal pulsed at least once immediately after a write enable period of the selected memory cell is ended.
6. The semiconductor integrated circuit system of claim 1 , wherein the phase-change compensation unit includes:
a resistance detection unit configured to detect a resistance of a phase-change area of the adjacent memory cell; and
a current generation unit configured to determine an amount of the correction current in response to a detection result of the resistance detection unit.
7. The semiconductor integrated circuit system of claim 1 , wherein the selected memory cell and the adjacent memory cell share common phase-change line.