Annealed seed layer to improve ferroelectric properties of memory layer
In some embodiments, the present disclosure relates to an integrated chip that includes a first conductive structure arranged over a substrate. A memory layer is arranged over the first conductive structure, below a second conductive structure, and includes a ferroelectric material. An annealed seed layer is arranged between the first and second conductive structures and directly on a first side of the memory layer. An amount of the crystal structure that includes an orthorhombic phase is greater than about 35 percent.
1. A method, comprising:
forming a seed layer over a substrate;
annealing the seed layer to form an annealed seed layer;
forming a memory layer over the annealed seed layer, wherein the memory layer is epitaxially grown from the anneal seed layer; and
forming a conductive structure over the memory layer;
wherein a thickness of the seed layer before the annealing is the same as a thickness of the annealed seed layer upon completion of the annealing.
2. The method according to claim 1 , further comprising:
forming a conductive layer over the substrate, wherein the seed layer is formed over and directly on the conductive layer, and wherein a thickness of the conductive layer before the annealing is the same as a thickness of the conductive layer upon completion of the annealing.
3. The method according to claim 1 , further comprising:
forming a semiconductor layer overlying the memory layer, wherein the conductive structure is formed atop the semiconductor layer; and
forming an additional conductive structure atop the semiconductor layer, laterally spaced from the conductive structure.
4. The method according to claim 1 , wherein the seed layer is formed by atomic layer deposition (ALD) of material from an oxygen-gas source and only one solid-precursor plate, and wherein the memory layer is formed by ALD of material from the oxygen-gas source and two solid-precursor plates.
5. The method according to claim 4 , wherein the seed layer and the memory layer both comprise material from a common solid-precursor plate.
6. The method according to claim 1 , further comprising:
forming a conductive layer over the substrate, wherein the seed layer is formed over and directly on the conductive layer, and wherein a thickness of the conductive layer before the forming of the seed layer is greater than a thickness of the conductive layer upon completion of the forming of the seed layer.
7. The method according to claim 1 , wherein the seed layer comprises metal oxide, and wherein the memory layer comprises hafnium zirconium oxide.
8. A method, comprising:
forming a seed layer overlying a substrate;
annealing the seed layer, wherein an orthorhombic crystalline phase increases in the seed layer from a beginning of the annealing to an end of the annealing;
forming a ferroelectric layer overlying and directly on the seed layer; and
forming a conductive structure overlying the ferroelectric layer;
wherein the forming of the seed layer and the annealing are performed within a common process chamber, wherein the forming of the seed layer comprises: adding a precursor vapor formed from an inert gas and a metal to the common process chamber; and adding an oxygen gas to the common process chamber after the adding the precursor vapor, and wherein the annealing is performed after the forming of the seed layer.
9. The method according to claim 8 , further comprising:
forming a conductive layer over the substrate, wherein the seed layer is formed over and directly on the conductive layer; and
patterning the conductive layer, the seed layer, and the ferroelectric layer into a memory cell.
10. The method according to claim 9 , wherein the seed layer is formed by oxidizing a top portion of the conductive layer.
11. The method according to claim 8 , wherein the annealing begins after the seed layer is formed and ends before the ferroelectric layer is formed.
12. The method according to claim 8 , wherein the seed layer comprises oxygen before the annealing.
13. The method according to claim 8 , further comprising:
forming a semiconductor layer overlying the ferroelectric layer, wherein the conductive structure is formed overlying the semiconductor layer.
14. A method, comprising:
forming a conductive wire over a substrate;
forming a memory cell atop the conductive wire and comprising:
a ferroelectric seed layer;
a semiconductor layer overlying the ferroelectric seed layer; and
a ferroelectric memory layer between the ferroelectric seed layer and the semiconductor layer, and directly contacting the ferroelectric seed layer; and
forming an etch stop layer;
wherein the etch stop layer is on sidewalls of the ferroelectric seed layer, and further has a top surface and a bottom surface respectively recessed relative to a top surface of the ferroelectric memory layer and elevated relative to a top surface of the conductive wire, after the forming of the memory cell and the forming of the etch stop layer.
15. The method according to claim 14 , wherein the ferroelectric seed layer and the etch stop layer have individual bottom surfaces level with each other after the forming of the memory cell and the forming of the etch stop layer.
16. The method according to claim 14 , further comprising:
forming an additional etch stop layer overlying and directly contacting a top surface of the semiconductor layer, wherein the additional etch stop layer is spaced from the etch stop layer.
17. The method according to claim 14 , further comprising:
forming an additional memory cell level with the memory cell and having another ferroelectric seed layer, which is spaced from the etch stop layer.
18. The method according to claim 8 , wherein a thickness of the seed layer before the annealing is the same as a thickness of the seed layer upon completion of the annealing.
19. The method according to claim 8 , wherein the forming of the seed layer further comprises forming the precursor vapor, which comprises flowing the inert gas over a solid precursor that comprises the metal and that is used during the forming of the ferroelectric layer.
20. The method according to claim 8 , further comprising:
forming a conductive layer over the substrate, wherein the forming of the seed layer further comprises, before the adding of the precursor vapor, adding the oxygen gas to the common process chamber to oxidize a top portion of the conductive layer and to form a first layer of the seed layer from the top portion, and wherein the adding of the precursor vapor and the adding of the oxygen gas after the adding of the precursor vapor form a second layer of the seed layer atop the first layer of the seed layer.