Memory cell array including ferroelectric capacitors, method for making the same, and ferroelectric memory device
A memory cell array is provided that includes ferroelectric capacitors with enhanced characteristics, a method of making the same, and a ferroelectric memory device including the memory cell. In a memory cell array, memory cells including ferroelectric capacitors are arrayed in a matrix. Each ferroelectric capacitor includes a lower electrode, an upper electrode, and a ferroelectric section disposed between the lower electrode and the upper electrode. The ferroelectric section is disposed in an intersection between the lower electrode and the upper electrode. An intermediate electrode is disposed between the ferroelectric section 14 and the upper electrode.
1. A memory cell array, comprising:
ferroelectric capacitors arrayed in a matrix, each ferroelectric capacitor including:
a lower electrode;
an upper electrode;
a ferroelectric section disposed between the lower electrode and the upper electrode; and
an intermediate electrode disposed between the ferroelectric section and the upper electrode,
the ferroelectric section including side surfaces not facing toward the upper and lower electrode,
the ferroelectric section and the intermediate electrode being disposed only in an intersection between the lower electrode and the upper electrode, and
a hydrogen barrier layer covering the entire side surfaces of the ferroelectric section.
2. A ferroelectric memory device, comprising:
the memory cell array according to claim 1 ; and
a hydrogen barrier film disposed above at least a plurality of the ferroelectric capacitors at a position covering the plurality of ferroelectric capacitors.
3. The ferroelectric memory device according to claim 2 , further comprising a peripheral circuit unit to selectively write or read information in or from the memory cells, the hydrogen barrier film being not disposed on the peripheral circuit unit.
4. The ferroelectric memory device according to claim 2 , further comprising an intralayer insulating layer disposed on the memory cell array, the hydrogen barrier film being disposed between the intralayer insulating layer and the memory cell array.
5. The ferroelectric memory device according to claim 4 , the hydrogen barrier film being disposed on the intralayer insulating layer.
6. The ferroelectric memory device according to claim 2 , the hydrogen barrier film functioning as an intralayer insulating layer.
7. A ferroelectric memory device, comprising:
the memory cell array according to claim 1 .
8. The memory cell array according to claim 1 ,
the upper electrodes extending in a first direction,
the lower electrodes extending in a second direction,
the ferroelectric section including first side surfaces facing in the first direction and the second side surfaces facing in the second direction,
the hydrogen barrier film including a first hydrogen barrier film covering the first side surfaces of the ferroelectric section and a second hydrogen barrier film covering the second side surfaces of the ferroelectric section.
9. The memory cell array according to claim 8 ,
the intermediate electrode including first side surfaces facing in the first direction and second side surfaces facing in the second direction,
the upper electrode including first side surfaces facing in the first direction and second side surfaces facing in the second direction,
the second hydrogen barrier film covering the second side surfaces of the intermediate electrode and the upper electrode, and an upper surface of the upper electrode.
10. The memory cell array according to claim 8 , an intralayer insulating layer being disposed on the first hydrogen barrier film.
11. The memory cell array according to claim 10 , a height of a surface of the intralayer insulating layer being the same as a height of a surface of the intermediate electrode.