Memory arrays, ferroelectric transistors, and methods of reading and writing relative to memory cells of memory arrays

Patent metadata

Field	Value
Publication number	US-10636471-B2
Application number	US-201615134221-A
Country	US
Kind code	B2
Filing date	Apr 20, 2016
Priority date	Apr 20, 2016
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

Some embodiments include a ferroelectric transistor. The transistor has gate dielectric material configured as a first container, with the first container having a first inner surface. Metal-containing material is configured as a second container nested within said first container. The second container has a second inner surface with an area less than the first inner surface. Ferroelectric material is configured as a third container nested within the second container. The third container has a third inner surface with an area less than the second inner surface. Gate material is within the third container. Some embodiments include memory arrays having ferroelectric transistors as memory cells. Some embodiments include methods of writing/reading relative to memory cells of memory arrays when the memory cells are metal-ferroelectric-metal-insulator-semiconductor (MFMIS) transistors.

First claim

We claim:

1. A ferroelectric transistor, comprising:
gate dielectric material configured as a first container, the first container having a first opening extending into the dielectric material and being defined by a first inner bottom surface and a first inner sidewall surface extending orthogonally relative to the first inner bottom surface;
metal-containing material configured as a second container nested within said first opening, the second container having a second opening extending into the metal containing material and being defined by a second inner bottom surface with an area less than the first inner surface and having a second inner sidewall surface extending orthogonally relative to the second inner bottom surface;
ferroelectric material configured as a third container nested within the second opening, the third container having a third inner bottom surface with an area less than the second inner surface and having a third inner sidewall surface extending orthogonally relative to the third inner bottom surface;
gate material within the third container; and
a common sidewall surface that extends orthogonally relative to the first, second and third inner bottom surfaces, each of the gate dielectric material, the metal-containing material, the ferroelectric material and the gate material being in direct physical contact with an insulative sidewall spacer material along the common sidewall surface.

2. The ferroelectric transistor of claim 1 wherein the first, second and third containers are elbow-shaped.

3. The ferroelectric transistor of claim 1 wherein an edge of the second container is inset relative to an edge of the first container.

4. The ferroelectric transistor of claim 3 wherein an edge of the third container is inset relative to an edge of the first container by about a same amount as the edge of the second container is inset relative to the edge of the first container.

5. The ferroelectric transistor of claim 3 wherein an edge of the third container is inset relative to an edge of the first container by a greater amount than the edge of the second container is inset relative to the edge of the first container.

6. The ferroelectric transistor of claim 3 wherein an edge of the third container is inset relative to an edge of the first container by about a lesser amount than the edge of the second container is inset relative to the edge of the first container.

7. The ferroelectric transistor of claim 1 wherein:
the first container has two sides defining about half of a four-sided structure, said two sides being a first side and a second side;
a third side of the four-sided structure extends along edges of the gate material, ferroelectric material, metal-containing material and gate dielectric material; the third side being directly adjacent the second side;
an insulative spacer extends entirely along said third side;
a first source/drain region is along a portion of the second side and extends to under the insulative spacer;
a second source/drain region is along a portion of the first side; and
a channel region extends along the first and second sides and between the first and second source/drain regions.

8. A memory array, comprising:
a plurality of ferroelectric transistors in a row/column arrangement; adjacent ferroelectric transistors along the columns being substantially mirror images of one another and having a shared source/drain region; each of the ferroelectric transistors comprising:
gate dielectric material configured as a first container having an opening extending into the gate dielectric material defined by a first inner base surface and first sidewall surface, the first container having two sides which define about half of a four-sided structure; the two sides being a first side and a second side;
metal-containing material configured as a second container nested within said first opening, the second container having a second inner base and sidewall surfaces, the second inner base surface having an area less than the first inner base surface;
ferroelectric material configured as a third container nested within the second container, the third container having a third inner base surface with an area less than the second inner base surface;
gate material within the third container; and
a third side of the four-sided structure extending orthogonally relative to the first, second and third inner base surfaces, the third side comprising edges of the gate material, ferroelectric material, metal-containing material and gate dielectric material, the third side being against an insulative sidewall spacer material such that each of the gate dielectric material, the metal containing material, the ferroelectric material and the gate material have surfaces in direct physical contact with the insulative sidewall spacer material; the third side being directly adjacent the second side; and

a repeating configuration of adjacent ferroelectric transistors along a column being a configuration in which the adjacent ferroelectric transistors face one another along their respective third sides and are spaced from one another by an intervening contact; the shared source/drain region being below the third sides of the adjacent ferroelectric transistors; said intervening contact extending to the shared source/drain region; the shared source/drain region being a first source/drain region and being laterally between a pair of second source/drain regions; one of the second source/drain regions being along the first side of one of the adjacent ferroelectric transistors and the other of the second source/drain regions being along the first side of the other of the adjacent ferroelectric transistors.

9. The memory array of claim 8 wherein each of the ferroelectric transistors has upper surfaces of the second and third containers inset relative to an upper surface of the first container.

10. The memory array of claim 8 , wherein:
ferroelectric transistors in a common row as one another have all of their gates electrically coupled to one another through a wordline;
ferroelectric transistors in a common column as one another are electrically coupled to two digit lines; a first of said two digit lines being electrically coupled with first source/drain regions, and a second of said two digit lines being electrically coupled with second source/drain regions; and
the ferroelectric transistors are memory cells, with a first data state of the memory cells corresponding to a first polarization mode of the ferroelectric material within the ferroelectric transistors and a second data state of the memory cells corresponding to a second polarization mode of the ferroelectric material within the ferroelectric transistors.

11. The memory array of claim 10 wherein the ferroelectric material is continuous along the rows of the array.

12. The memory array of claim 10 wherein the ferroelectric material is not continuous along the rows of the array.

13. The memory array of claim 10 wherein the gate dielectric material is continuous along the rows of the array.

14. The memory array of claim 10 wherein the gate dielectric material is not continuous along the rows of the array.

15. A method of writing to memory cells of memory array wherein the memory array comprises:
a plurality of ferroelectric transistors in a row/column arrangement; adjacent ferroelectric transistors along the columns being substantially mirror images of one another and having a shared source/drain region; each of the ferroelectric transistors comprising:
gate dielectric material configured as a first container having an opening extending into th

Assignees

• Micron Technology Inc

Inventors

• Ramaswamy Durai Vishak Nirmal
• Kinney Wayne

Classifications

• G11C11/2275 Primary

  Writing or programming circuits or methods · CPC title

• G11C11/2257

  Word-line or row circuits · CPC title

• G11C11/2273

  Reading or sensing circuits or methods · CPC title

• G11C11/223

  using MOS with ferroelectric gate insulating film · CPC title

• H01L27/11507

  Electricity · mapped topic