Semiconductor switching devices having ferroelectric layers therein and methods of fabricating same
A semiconductor device includes a substrate, a channel on or in the substrate, a source/drain pair respectively on opposite ends of the channel, and a gate structure on the channel between the source/drain pair, wherein the gate structure includes an interfacial layer, a ferroelectric layer, a stabilization layer, an oxygen diffusion barrier layer, and a threshold voltage control layer that are sequentially stacked on the channel.
1. A semiconductor device, comprising:
a substrate comprising a first region and a second region;
a first gate structure on the first region of the substrate, said first gate structure comprising a first interfacial layer, a first ferroelectric layer, a first stabilization layer, a first oxygen diffusion barrier layer, and a first threshold voltage control layer that are sequentially stacked on the first region of the substrate; and
a second gate structure on the second region of the substrate, said second gate structure comprising a second interfacial layer, a second ferroelectric layer, a second stabilization layer, and a second threshold voltage control layer directly on the second stabilization layer, which are sequentially stacked on the second region of the substrate;
wherein the first stabilization layer is configured to stabilize a ferroelectric phase of the first ferroelectric layer to thereby preserve a ferroelectricity characteristic of the first ferroelectric layer; and
wherein the second stabilization layer is configured to stabilize a ferroelectric phase of the second ferroelectric layer to thereby preserve a ferroelectricity characteristic of the second ferroelectric layer.
2. The device of claim 1 , wherein the first interfacial layer has a thickness in a range from 1 Å to 10 Å.
3. The device of claim 1 , wherein the first stabilization layer and the first threshold voltage control layer comprise different materials.
4. The device of claim 3 , wherein a material included in the first stabilization layer has a work function that is greater than a work function of a material included in the first threshold voltage control layer.
5. The device of claim 1 , wherein the first stabilization layer comprises at least one material selected from a group consisting of TiN, MoN, Mo, Al 2 O 3 , AlN, W, WN, WCN, La, LaO, LaN, TiAlN, and TiON.
6. The device of claim 1 , wherein the first oxygen diffusion barrier layer comprises at least one material selected from a group consisting of TiN, AlN, TaN, TiSiN, TiON, TiAlN, WCN, WN, and W.
7. The device of claim 1 , wherein the first stabilization layer has a thickness that is equivalent to a thickness of the second stabilization layer.
8. The device of claim 1 , wherein the first stabilization layer and the second stabilization layer comprise the same material.
9. The device of claim 1 , wherein the first threshold voltage control layer comprises a first lower threshold voltage control layer on the first stabilization layer and a first upper threshold voltage control layer on the first lower threshold voltage control layer; and wherein the second threshold voltage control layer comprises a second lower threshold voltage control layer on the second ferroelectric layer and a second upper threshold voltage control layer on the second lower threshold voltage control layer.
10. The device of claim 9 , wherein a material included in the first stabilization layer has a work function that is greater than a work function of a material included in the first upper threshold voltage control layer.
11. The device of claim 9 , wherein a material included in the first stabilization layer has a work function that is greater than a work function of a material included in the first lower threshold voltage control layer.