Memory cells

Patent metadata

Field	Value
Publication number	US-9887204-B2
Application number	US-201715584371-A
Country	US
Kind code	B2
Filing date	May 2, 2017
Priority date	Feb 17, 2015
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

A memory cell includes a select device and a capacitor electrically coupled in series with the select device. The capacitor includes two conductive capacitor electrodes having ferroelectric material there-between. The capacitor has an intrinsic current leakage path from one of the capacitor electrodes to the other through the ferroelectric material. There is a parallel current leakage path from the one capacitor electrode to the other. The parallel current leakage path is circuit-parallel the intrinsic path and of lower total resistance than the intrinsic path. Other aspects are disclosed.

First claim

The invention claimed is:

1. A memory cell, comprising:
a capacitor comprising:
a first conductive capacitor electrode having a base and laterally-spaced walls extending there-from;
a second conductive capacitor electrode laterally between the walls of the first capacitor electrode; and
ferroelectric material laterally between the walls of the first capacitor electrode and laterally between the second capacitor electrode and the first capacitor electrode, the capacitor comprising an intrinsic current leakage path from one of the first and second capacitor electrodes to the other through the ferroelectric material; and

a parallel current leakage path between the second capacitor electrode and a surface of the base of the first capacitor electrode, the parallel current leakage path being circuit-parallel the intrinsic current leakage path and of lower total resistance than the intrinsic current leakage path.

2. The memory cell of claim 1 wherein the parallel path where between the second capacitor electrode and the surface of the base of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV not being directly against lateral side surfaces of the laterally-spaced walls of the first capacitor electrode.

3. The memory cell of claim 1 wherein the parallel path where between the second capacitor electrode and the surface of the base of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV being directly against the surface of the base of the first capacitor electrode.

4. The memory cell of claim 3 wherein the ferroelectric material comprises laterally-spaced walls having side surfaces, the material having dominant band gap of 0.4 eV to 5.0 eV being directly against the side surfaces of the laterally-spaced walls of the ferroelectric material.

5. The memory cell of claim 1 wherein,
the ferroelectric material has a base and laterally-spaced walls extending there-from; and
the parallel path where between the second capacitor electrode and the surface of the base of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV extending through the base of the ferroelectric material.

6. The memory cell of claim 5 wherein the material having dominant band gap of 0.4 eV to 5.0 eV is not directly against lateral side surfaces of the laterally-spaced walls of the ferroelectric material.

7. A memory cell, comprising:
a capacitor comprising:
a first conductive capacitor electrode having laterally-spaced walls;
a second conductive capacitor electrode laterally between the walls of the first capacitor electrode; and
ferroelectric material laterally between the walls of the first capacitor electrode and laterally between the second capacitor electrode and the first capacitor electrode, the capacitor comprising an intrinsic current leakage path from one of the first and second capacitor electrodes to the other through the ferroelectric material; and

a parallel current leakage path between the second capacitor electrode and a surface of the laterally-spaced walls of the first capacitor electrode, the parallel current leakage path being circuit-parallel the intrinsic current leakage path and of lower total resistance than the intrinsic current leakage path.

8. The memory cell of claim 7 wherein the parallel path where between the second capacitor electrode and the surface of the laterally-spaced walls of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV comprising an annulus.

9. The memory cell of claim 7 wherein the parallel path where between the second capacitor electrode and the surface of the laterally-spaced walls of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV being directly against the surface of the laterally-spaced walls of the first capacitor electrode.

10. The memory cell of claim 9 wherein the surface comprises a lateral side surface of the laterally-spaced walls of the first capacitor electrode.

11. The memory cell of claim 9 wherein the first capacitor electrode has a base from which the laterally-spaced walls extend, the material having dominant band gap of 0.4 eV to 5.0 eV being directly against a surface of the base of the first capacitor electrode.

12. The memory cell of claim 9 wherein the surface comprises an elevationally outermost surface of the laterally-spaced walls of the first capacitor electrode.

13. The memory cell of claim 12 wherein the ferroelectric material comprises an elevationally outermost surface, the material having dominant band gap of 0.4 eV to 5.0 eV being directly against the elevationally outermost surface of the ferroelectric material.

14. A memory cell, comprising:
a capacitor comprising:
a first conductive capacitor electrode comprising an annulus;
a second conductive capacitor electrode radially within the annulus of the first capacitor electrode; and
ferroelectric material radially within the annulus of the first capacitor electrode between the second capacitor electrode and the first capacitor electrode, the capacitor comprising an intrinsic current leakage path from one of the first and second capacitor electrodes to the other through the ferroelectric material; and

a parallel current leakage path between the second capacitor electrode and a surface of the annulus of the first capacitor electrode, the parallel current leakage path being circuit-parallel the intrinsic current leakage path and of lower total resistance than the intrinsic current leakage path.

15. The memory cell of claim 14 wherein the parallel path where between the second capacitor electrode and the surface of the annulus of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV comprising an annulus.

16. The memory cell of claim 14 wherein,
the surface of the annulus is an elevationally outermost surface of the annulus; and
the parallel path where between the second capacitor electrode and the surface of the annulus of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV being directly against the elevationally outermost surface of the annulus.

17. The memory cell of claim 14 wherein,
the ferroelectric material comprises an annulus having an elevationally outermost surface; and
the parallel path where between the second capacitor electrode and the surface of the annulus of the first capacitor electrode is within and through material having a dominant band gap of 0.4 eV to 5.0 eV, the material having dominant band gap of 0.4 eV to 5.0 eV being directly against the elevationally outermost surface of the ferroelectric material.

18. A memory cell, comprising:
a select device;
a capacitor electrically coupled in series with the select device, the capacitor comprising:
a first conductive capacitor electrode having laterally-spaced walls extending there-from;
a second conductive capacitor electrode laterally between the walls of the first capacitor

Assignees

• Micron Technology Inc

Inventors

• Karda Kamal M
• Tao Qian
• Ramaswamy Durai Vishak Nirmal
• Liu Haitao
• Prall Kirk D
• Chavan Ashonita A

Classifications

• H01G4/08

  Inorganic dielectrics · CPC title

• H01G4/008 Primary

  Selection of materials · CPC title

• H01G4/33

  Thin- or thick-film capacitors {(thin- or thick-film circuits; capacitors without a potential-jump or surface barrier specially adapted for integrated circuits, details thereof, multistep manufacturing processes therefor)} · CPC title

• H01G4/40

  Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations · CPC title

• H01L28/75

  Electricity · mapped topic