Capping layer over FET FeRAM to increase charge mobility
In some embodiments, the present disclosure relates to an integrated chip that includes a gate electrode over a substrate, and a gate dielectric layer arranged over the gate electrode. The gate dielectric layer includes a ferroelectric material. An active structure is arranged over the gate dielectric layer and includes a semiconductor material. A source contact and a drain contact are arranged over the active structure. A capping structure is arranged between the source and drain contacts and over the active structure. The capping structure includes a first metal material.
1. An integrated chip, comprising:
a gate electrode arranged over a substrate;
a gate dielectric layer arranged over the gate electrode and comprising a ferroelectric material;
an active structure arranged over the gate dielectric layer and comprising a semiconductor material;
a source contact and a drain contact arranged over the active structure; and
a capping structure arranged over the active structure and between the source contact and the drain contact,
wherein the capping structure comprises a first metal material and directly contacts a diffusion region of the active structure, and wherein the diffusion region comprises the first metal material and a first material of the active structure.
2. The integrated chip of claim 1 ,
wherein the active structure comprises a stack of cocktail layers alternating with first active layers,
wherein the cocktail layers comprise a mixture of the first material and a second material,
wherein the first active layers comprise a third material different than the first and second materials,
wherein a bottommost layer of the active structure is one of the cocktail layers, and
wherein a topmost layer of the active structure is arranged over the stack of cocktail layers alternating with first active layers and comprises the first material.
3. The integrated chip of claim 1 , wherein the active structure comprises a stack of first active layers comprising a first metal oxide material, second active layers comprising a second metal oxide material, and third active layers comprising a third metal oxide material.
4. The integrated chip of claim 1 , wherein the capping structure comprises a first layer comprising the first metal material and a second layer arranged over the first layer and comprising a second metal material.
5. The integrated chip of claim 1 , wherein the capping structure is grounded.
6. The integrated chip of claim 1 , wherein the first metal material has a higher affinity for oxygen than materials of the active structure.
7. The integrated chip of claim 1 , wherein the active structure comprises a lower portion comprising a mixture of the first material, a second material, and a third material, and wherein the active structure comprises an upper portion arranged over the lower portion and comprising the first material.
8. An integrated chip comprising:
a gate electrode arranged over a substrate;
a gate dielectric layer arranged over the gate electrode, wherein the gate dielectric layer comprises a ferroelectric material;
an active structure arranged over the gate dielectric layer;
a source contact and a drain contact arranged over the active structure; and
a capping structure arranged over the active structure and between the source contact and the drain contact,
wherein the capping structure comprises a first metal material that has a higher affinity for oxygen than metals in the active structure.
9. The integrated chip of claim 8 ,
wherein the active structure comprises a first material, a second material that is different than the first material, and a third material that is different than the first and second materials,
wherein the first material and the second material directly contact the gate dielectric layer,
wherein the third material is spaced apart from the gate dielectric layer by the first and second materials, and
wherein the capping structure directly contacts the first material and not the second or third materials.
10. The integrated chip of claim 8 , wherein the capping structure comprises a first layer comprising the first metal material and a second layer comprising a second metal material and arranged over the first layer.
11. The integrated chip of claim 10 , wherein the first layer directly contacts a diffusion region of the active structure, and wherein the diffusion region comprises the first metal material and oxygen.
12. The integrated chip of claim 8 , wherein the capping structure comprises a mixture of the first metal material and a second metal material.
13. The integrated chip of claim 8 , further comprising:
an interconnect via arranged below and coupled to the gate electrode;
a first interconnect wire arranged over and coupled to the source contact;
a second interconnect wire arranged over and coupled to the drain contact; and
an interconnect dielectric structure surrounding the interconnect via, the first interconnect wire, the second interconnect wire, the source contact, the drain contact, and the capping structure.
14. The integrated chip of claim 8 , wherein the capping structure is grounded.
15. The integrated chip of claim 8 , wherein a topmost layer of the active structure comprises gallium oxide, and a bottommost layer of the active structure comprises a mixture of gallium oxide and indium oxide.
16. A method comprising:
forming a gate electrode over a substrate;
forming a gate dielectric layer comprising a ferroelectric material over the gate electrode;
forming an active structure over the gate dielectric layer;
forming a first metal layer over the active structure;
removing peripheral portions of the first metal layer to form a capping structure over the active structure; and
forming a source contact and a drain contact over the active structure, wherein the capping structure is arranged laterally between the source contact and the drain contact.
17. The method of claim 16 , wherein the forming of the active structure comprises:
forming a cocktail layer over the gate dielectric layer by activating two precursors at one time such that the cocktail layer comprises a mixture of a first material and a second material;
forming a first active layer over the cocktail layer comprising a third material different than the first and second materials; and
repeating the forming of the cocktail layer and the first active layer to form a stack of cocktail layers and first active layers alternating with one another over the gate dielectric layer; and
forming a topmost active layer comprising the first material over the stack of cocktail layers and first active layers.
18. The method of claim 16 , further comprising:
forming a second metal layer over the first metal layer; and
removing peripheral portions of the second metal layer, wherein the capping structure comprises the first and second metal layers.
19. The method of claim 16 , wherein the first metal layer is formed using solid precursors and an atomic layer deposition process.
20. The method of claim 16 , further comprising:
performing a thermal annealing process after the formation of the first metal layer and before forming the source and drain contacts.