Semiconductor memory device
View Patent ↗To realize a semiconductor memory device whose capacitance value per unit area in a memory cell is increased without increase in the area of the memory cell. The memory cell includes a transistor, a memory element, a first capacitor, and a second capacitor. The first capacitor includes a semiconductor film, a gate insulating film, and a gate electrode which are included in the transistor and is formed at the same time as the transistor. The second capacitor includes an electrode which is included in the memory element and an insulating film and an electrode which are formed over the electrode. Further, the second capacitor is formed over the first capacitor. In this manner, the first capacitor and the second capacitor which are connected in parallel with the memory element are formed.
1. A semiconductor device comprising a memory cell, the memory cell comprising:
a transistor including a first semiconductor film, a gate insulating film over the first semiconductor film, a gate electrode over the gate insulating film, a source electrode, and a drain electrode;
a memory element including a first electrode, a second semiconductor film over the first electrode, and a second electrode over the second semiconductor film;
a first capacitor including a third electrode, a first insulating film over the third electrode, and a fourth electrode over the first insulating film; and
a second capacitor over the first capacitor, the second capacitor including a fifth electrode, a second insulating film over the fifth electrode, and a sixth electrode over the second insulating film,
wherein one of the source electrode and the drain electrode is electrically connected to the second electrode, the third electrode, and the fifth electrode,
wherein the first electrode is electrically connected to the fourth electrode and the sixth electrode,
wherein the gate insulating film and the first insulating film are formed by using the same material,
wherein the gate electrode, the first electrode and the fourth electrode are formed by using the same material, and
wherein the source electrode, the drain electrode, the second electrode, and the fifth electrode are formed by using the same material.
2. The semiconductor device according to claim 1 , wherein the memory element is formed over the first capacitor.
3. The semiconductor device according to claim 1 , wherein the first electrode and the fourth electrode are formed by using the same conductive layer.
4. The semiconductor device according to claim 1 ,
wherein the third electrode is formed by using a third semiconductor film including an impurity, and
wherein the first semiconductor film and the third semiconductor film are formed by using the same material.
5. The semiconductor device according to claim 1 , wherein the memory element, the first capacitor, and the second capacitor are connected in parallel.
6. The semiconductor device according to claim 1 , wherein the gate insulating film, the first insulating film, and the second insulating film include silicon nitride.
7. The semiconductor device according to claim 1 , wherein the second semiconductor film causes silicide reaction with the first electrode when high voltage potential is applied between the first electrode and the second electrode.
8. The semiconductor device according to claim 1 , wherein the second insulating film is provided over the transistor.
9. A semiconductor device comprising a memory cell, the memory cell comprising:
a transistor including a first semiconductor film, a gate insulating film over the first semiconductor film, a gate electrode over the gate insulating film, a source electrode, and a drain electrode;
a memory element including a first electrode, a second semiconductor film over the first electrode, and a second electrode over the second semiconductor film;
a first capacitor including a third electrode, a first insulating film over the third electrode, and a fourth electrode over the first insulating film;
a second capacitor over the first capacitor, the second capacitor including a fifth electrode, a second insulating film over the fifth electrode, and a sixth electrode over the second insulating film; and
a third capacitor over the second capacitor, the third capacitor including a seventh electrode, a third insulating film over the seventh electrode, and an eighth electrode over the third insulating film,
wherein one of the source electrode and the drain electrode is electrically connected to the second electrode, the third electrode, the fifth electrode, and the seventh electrode,
wherein the first electrode is electrically connected to the fourth electrode, the sixth electrode, and the eighth electrode,
wherein the gate insulating film and the first insulating film are formed by using the same material,
wherein the gate electrode, the first electrode and the fourth electrode are formed by using the same material, and
wherein the source electrode, the drain electrode, the second electrode, and the fifth electrode are formed by using the same material.
10. The semiconductor device according to claim 9 , wherein the memory element is formed over the first capacitor.
11. The semiconductor device according to claim 9 , wherein the first electrode and the fourth electrode are formed by using the same conductive layer.
12. The semiconductor device according to claim 9 ,
wherein the third electrode is formed by using a third semiconductor film including an impurity, and
wherein the first semiconductor film and the third semiconductor film are formed by using the same material.
13. The semiconductor device according to claim 9 , wherein the memory element, the first capacitor, the second capacitor, and the third capacitor are connected in parallel.
14. The semiconductor device according to claim 9 , wherein the gate insulating film, the first insulating film, the second insulating film, and the third insulating film include silicon nitride.
15. The semiconductor device according to claim 9 , wherein the second semiconductor film causes silicide reaction with the first electrode when high voltage potential is applied between the first electrode and the second electrode.
16. The semiconductor device according to claim 9 , wherein the second insulating film is provided over the transistor.