Ferroelectric memory device having vertical channel between source line and bit line
A ferroelectric memory device according to an embodiment includes a base conduction layer, a channel layer extending in a vertical direction from the base conduction layer, a ferroelectric layer disposed on the channel layer, a plurality of ferroelectric memory cell transistor stacked in a vertical direction on the base conduction layer, a control transistor disposed over the plurality of ferroelectric memory cell transistors, and a bit line pattern electrically connected to the channel layer.
1. A ferroelectric memory device comprising:
a base conduction layer;
a channel layer extending in a vertical direction from the base conduction layer;
a ferroelectric layer disposed on the channel layer;
a plurality of ferroelectric memory cell transistors stacked in a vertical direction on the base conduction layer, each of the ferroelectric memory cell transistors comprising a portion of the ferroelectric layer and a memory gate electrode layer disposed on the ferroelectric layer in a horizontal direction;
a control transistor disposed over the plurality of ferroelectric memory cell transistors comprising a control dielectric layer disposed on the channel layer and a control gate electrode layer disposed on the control dielectric layer in a horizontal direction; and
a bit line pattern electrically connected to the channel layer,
wherein the memory gate electrode layers and the control gate electrode layer each comprise at least one of tungsten (W), titanium (Ti), copper (Cu), ruthenium (Ru), tungsten nitride (WN), titanium nitride (TiN), tantalum nitride (TaN), ruthenium oxide (RuO2), tungsten carbide (WC), titanium carbide (TiC), tungsten silicide (WSi2), titanium silicide (TiSi2), and tantalum silicide (TaSi2).
2. The ferroelectric memory device of claim 1 , wherein the plurality of ferroelectric memory cell transistors and the control transistor share the channel layer.
3. The ferroelectric memory device of claim 1 , wherein the ferroelectric memory cell transistors further comprise a plurality of interlayer insulating layers, wherein the interlayer insulating layers are alternately stacked with the memory gate electrodes in a vertical direction from the base conduction layer.
4. The ferroelectric memory device of claim 1 , wherein the channel layer comprises an n-type or a p-type doped semiconductor material.
5. The ferroelectric memory device of claim 1 , wherein the ferroelectric layer comprises at least one of hafnium oxide, zirconium oxide, and hafnium zirconium oxide.
6. The ferroelectric memory device of claim 1 , wherein the ferroelectric layer comprises at least one of carbon (C), silicon (Si), magnesium (Mg), aluminum (Al), yttrium (Y), nitrogen (N), germanium (Ge), tin (Sn), strontium (Sr), lead (Pb), calcium (Ca), barium (Ba), titanium (Ti), zirconium (Zr), and gadolinium (Ga) as a dopant.
7. The ferroelectric memory device of claim 1 , wherein the control dielectric layer comprises a paraelectric material, and wherein the paraelectric material comprises at least one of silicon oxide, silicon nitride, aluminum oxide, silicon oxynitride, hafnium oxide and zirconium oxide.
8. A ferroelectric memory device comprising:
a base conduction layer;
a channel layer extending in a vertical direction from the base conduction layer;
a ferroelectric structure;
a plurality of ferroelectric memory cell transistors stacked in a vertical direction on the base conduction layer, each of the ferroelectric memory cell transistors including a portion of the ferroelectric structure adjacent to the channel layer and a memory gate electrode layer disposed on the ferroelectric structure; and
a bit line pattern electrically connected to the channel layer over the plurality of ferroelectric memory cell transistors,
wherein the ferroelectric structure comprises a first ferroelectric layer and a second ferroelectric layer,
wherein both of the first ferroelectric layer and the second ferroelectric layer have ferroelectricity, and
wherein a coercive field of the first ferroelectric layer is different from a coercive field of the second ferroelectric layer.
9. The ferroelectric memory device of claim 8 , wherein the ferroelectric structure further comprises an interfacial insulating layer in contact with the channel layer.
10. The ferroelectric memory device of claim 8 , wherein the first ferroelectric layer and the second ferroelectric layer comprise at least one of hafnium oxide, zirconium oxide, and hafnium zirconium oxide.
11. The ferroelectric memory device of claim 10 , wherein at least one of the first ferroelectric layer and the second ferroelectric layer comprises a dopant comprising at least one of carbon (C), silicon (Si), magnesium (Mg), aluminum (Al), yttrium (Y), nitrogen (N), germanium (Ge), tin (Sn), strontium (Sr), lead (Pb), calcium (Ca), barium (Ba), titanium (Ti), zirconium (Zr), and gadolinium (Ga).
12. The ferroelectric memory device of claim 8 , wherein the first ferroelectric layer and the second ferroelectric layer have a different dopant concentration.
13. The ferroelectric memory device of claim 8 , wherein the first ferroelectric layer and the second ferroelectric layer have a different grain size with each other.
14. The ferroelectric memory device of claim 8 , wherein the ferroelectric structure has a plurality of remanent polarization based on the coercive fields of the first ferroelectric layer and the second ferroelectric layer.