Method of forming a semiconductor structure including a ferroelectric material and semiconductor structure including a ferroelectric transistor

Patent metadata

Field	Value
Publication number	US-9412600-B2
Application number	US-201414471812-A
Country	US
Kind code	B2
Filing date	Aug 28, 2014
Priority date	Aug 28, 2014
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

An illustrative method disclosed herein includes providing a semiconductor structure. The semiconductor structure includes a logic transistor region, a ferroelectric transistor region and an input/output transistor region. A first protection layer is formed over the semiconductor structure. The first protection layer covers the logic transistor region and the input/output transistor region. At least a portion of the ferroelectric transistor region is not covered by the first protection layer. After the formation of the first protection layer, a ferroelectric transistor dielectric is deposited over the semiconductor structure, the ferroelectric transistor dielectric and the first protection layer are removed from the logic transistor region and the input/output transistor region, an input/output transistor dielectric is formed over the input/output transistor region and a logic transistor dielectric is formed over at least the logic transistor region.

First claim

What is claimed:

1. A method, comprising:
providing a semiconductor structure comprising a logic transistor region, a ferroelectric transistor region and an input/output transistor region;
forming a first protection layer over said semiconductor structure, said first protection layer covering said logic transistor region and said input/output transistor region, at least a portion of said ferroelectric transistor region not being covered by said first protection layer;
after forming said first protection layer, forming a recess in said ferroelectric transistor region by performing an etch process adapted to remove a semiconductor material of said ferroelectric transistor region;
after said etch process, performing an oxidation process adapted to oxidize said semiconductor material of said ferroelectric transistor region and performing a wet etch adapted to remove an oxide formed in said oxidation process; and
depositing a ferroelectric transistor dielectric over said semiconductor structure, wherein a portion of said ferroelectric transistor dielectric is deposited in said recess, removing said ferroelectric transistor dielectric and said first protection layer from said logic transistor region and said input/output transistor region, forming an input/output transistor dielectric over said input/output transistor region, and forming a logic transistor dielectric over at least said logic transistor region.

2. The method of claim 1 , wherein the formation of said input/output transistor dielectric comprises:
forming said input/output transistor dielectric over at least said input/output transistor region and said logic transistor region; and
removing said input/output transistor dielectric from at least said logic transistor region.

3. The method of claim 2 , further comprising, after removing said input/output transistor dielectric from at least said logic transistor region, depositing a logic transistor dielectric over said semiconductor structure and depositing a first metal over said logic transistor dielectric.

4. The method of claim 3 , further comprising:
after removing said ferroelectric transistor dielectric and said first protection layer from said ferroelectric transistor region, depositing a second protection layer over said semiconductor structure; and
removing portions of said second protection layer over said logic transistor region and said input/output transistor region, a portion of said second protection layer covering said ferroelectric transistor region remaining in said semiconductor structure;
wherein said input/output transistor dielectric is formed after said removing portions of said second protection layer over said logic transistor region and said input/output transistor region.

5. The method of claim 4 , wherein said logic transistor dielectric and said first metal are removed from said ferroelectric transistor region together with a portion of said second protection layer over said ferroelectric transistor region.

6. The method of claim 5 , further comprising, after removing said portion of said second protection layer over said ferroelectric transistor region, said first metal and said logic transistor dielectric from said ferroelectric transistor region, removing said first metal from said logic transistor region and said input/output transistor region, depositing a second metal over said semiconductor structure and depositing a layer of a semiconductor material over said semiconductor structure.

7. The method of claim 6 , further comprising, before the formation of said first protection layer, forming a pad layer over said logic transistor region, said ferroelectric transistor region and said input/output transistor region.

8. The method of claim 7 , wherein, in the removal of said first protection layer from said ferroelectric transistor region, said pad layer is used as an etch stop layer.

9. The method of claim 8 , wherein, in the removal of said first protection layer from said logic transistor region and said input/output transistor region, said pad layer is used as an etch stop layer.

10. The method of claim 9 , wherein said ferroelectric transistor dielectric comprises a layer of silicon-doped hafnium dioxide.

11. The method of claim 1 , wherein said recess is entirely filled with said ferroelectric transistor dielectric.

12. The method of claim 1 , further comprising performing one or more ion implantation processes for forming a doped well region in each of said logic transistor region, said ferroelectric transistor region and said input/output transistor region, wherein said one or more ion implantation processes are performed after said oxidation process.

13. The method of claim 11 , wherein the formation of said recess comprises performing an oxidation process adapted to oxidize a semiconductor material of said ferroelectric transistor region and performing an etch process adapted to remove an oxide formed in said oxidation process, wherein substantially all of said semiconductor material of said ferroelectric transistor region that is removed in the formation of said recess is oxidized in said oxidation process.

14. The method of claim 13 , further comprising performing one or more ion implantation processes for forming a doped well region in each of said logic transistor region, said ferroelectric transistor region and said input/output transistor region, wherein said one or more ion implantation processes are performed after said oxidation process.

15. The method of claim 14 , wherein said etch process adapted to remove said oxide is performed before said one or more ion implantation processes.

16. The method of claim 4 , wherein said etch process adapted to remove said oxide is performed after said one or more ion implantation processes.

17. The method of claim 1 , further comprising:
forming a first gate electrode over said ferroelectric transistor region;
forming a second gate electrode over said logic transistor region; and
forming a third gate electrode over said input/output transistor region.

18. The method of claim 17 , further comprising:
depositing a layer of a gate electrode material over said semiconductor structure;
wherein the formation of said first gate electrode comprises performing a first gate etch process adapted to remove said gate electrode material, said first gate etch process partially removing a portion of said layer of gate electrode material over said ferroelectric transistor region; and
wherein the formation of said second gate electrode and said third gate electrode comprises performing a second gate etch process, said second gate etch process partially removing a portion of said layer of gate electrode material over said logic transistor region and a portion of said layer of gate electrode material over said input/output transistor region;
said first gate etch process and said second gate etch process being separate etch processes.

19. The method of claim 18 , further comprising:
depositing a layer of a hardmask material over said semiconductor structure;
patterning said layer of hardmask material to form a hardmask from said layer of hardmask material, said hardmask comprising a first portion over said ferroelectric transistor region defining said first gate electrode, a second portion over said logic transistor region defining said second gate electrode and a third portion over said input/output transistor region defining said third gate electrode, said first gate etch process and said second gate etch process being performed in the presence of s

Assignees

• Globalfoundries Inc

Inventors

• Van Bentum Ralf
• Grasshoff Gunter

Classifications

• H10D64/0134

  with a treatment, e.g. annealing, after the formation of the insulator and before the formation of the conductor · CPC title

• H10D64/691

  comprising metallic compounds, e.g. metal oxides or metal silicates  (insulators comprising nitrogen H10D64/693) · CPC title

• H10D64/685

  being perpendicular to the channel plane · CPC title

• H10D64/667

  the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671) · CPC title

• H10D84/0144

  Manufacturing their gate insulating layers · CPC title