Memory device including control gates having tungsten structure
Some embodiments include apparatuses and methods of forming the apparatuses. One of the apparatuses includes a first dielectric material; a second dielectric material separated from the first dielectric material; a memory cell string including a pillar extending through the first and second dielectric materials, the pillar including a portion between the first and second dielectric materials; and a tungsten material located between the first and second dielectric materials and separated from the portion of the pillar and the first and second dielectric materials by an additional dielectric material. The additional dielectric material has a dielectric constant greater than a dielectric constant of silicon dioxide. The additional dielectric material contacts the portion of the pillar and the tungsten material.
1. An apparatus, comprising:
a first dielectric material;
a second dielectric material separated from the first dielectric material;
a memory cell string including a pillar extending through the first dielectric material and the second dielectric material, the pillar including a portion between the first and second dielectric materials; and
a tungsten material having different crystal structures and located between the first dielectric material and the second dielectric material, the tungsten material separated from the portion of the pillar, from the first dielectric material and from the second dielectric materials by an additional dielectric material, the additional dielectric material having a dielectric constant greater than a dielectric constant of a silicon dioxide, wherein the additional dielectric material directly and physically contacts the portion of the pillar and the tungsten material.
2. The apparatus of claim 1 , wherein at least a portion of the tungsten material is a beta-phase tungsten.
3. The apparatus of claim 1 , wherein the tungsten material includes:
a first portion of tungsten contacting the additional dielectric material, wherein a majority of the first portion of tungsten is a beta-phase tungsten; and
a second portion of tungsten contacting the first portion of tungsten, wherein a majority of the second portion of tungsten is an alpha-phase tungsten.
4. The apparatus of claim 3 , wherein the majority of the second portion of tungsten has a grain size having a maximum dimension of at least 80 nanometers.
5. The apparatus of claim 4 , wherein at least 50% of the second portion of tungsten has a grain size with a maximum dimension of at least 100 nanometers.
6. The apparatus of claim 3 , wherein a resistivity of the first portion of tungsten is higher than that of the second portion of tungsten.
7. The apparatus of claim 1 , wherein the first dielectric material includes a first silicon dioxide different from the additional dielectric material, and the second dielectric material includes a second silicon dioxide different from the additional dielectric material.
8. The apparatus of claim 1 , wherein the additional dielectric material includes aluminum oxide.
9. The apparatus of claim 1 , wherein the additional dielectric material contains hafnium.
10. The apparatus of claim 1 , wherein the additional dielectric material contains zirconium.
11. An apparatus, comprising:
a first dielectric material;
a second dielectric material separated from the first dielectric material;
a memory cell string including a pillar extending through the first dielectric material and the second dielectric material, the pillar including a first additional dielectric material between the first dielectric material and the second dielectric material; and
a tungsten material having different crystal structures and located between the first dielectric material and the second dielectric material and directly and physically contacting the first additional dielectric material of the pillar, the tungsten material is separated from the first dielectric material and the second dielectric material by a second additional dielectric material, each of the first additional dielectric material and the second additional dielectric material having a dielectric constant greater than a dielectric constant of a silicon dioxide, wherein at least a portion of the tungsten material is a beta-phase tungsten.
12. The apparatus of claim 11 , wherein the first dielectric material includes a first silicon dioxide different from the first additional dielectric material and the second additional dielectric material, and the second dielectric material includes a second silicon dioxide different from the additional dielectric material and the second additional dielectric material.
13. The apparatus of claim 11 , wherein the first additional dielectric material and the second additional dielectric material have a same dielectric material.
14. The apparatus of claim 11 , wherein the first additional dielectric material and the second additional dielectric material contain one of aluminum oxide, hafnium, and zirconium.
15. An apparatus, comprising:
control gates for a memory cell string, the control gates interleaved with dielectric materials, the control gates including a control gate located between a first dielectric material of the dielectric materials and a second dielectric material of the dielectric materials; and
a pillar of the memory cell string extending through the control gates and the dielectric materials, the pillar including a portion between the first dielectric material and the second dielectric material, wherein the control gate is separated from the portion of the pillar by an additional dielectric material, the control gate is made of tungsten with different crystal structures and includes a portion of the tungsten directly and physically contacting the additional dielectric material, and a majority of the portion of the tungsten is a beta-phase tungsten.
16. The apparatus of claim 15 , wherein the control gate includes an additional portion of the tungsten contacting the portion of the tungsten, and a majority of the additional portion of the tungsten is an alpha-phase tungsten.
17. The apparatus of claim 16 , wherein the majority of the additional portion of the tungsten has a grain size having a maximum dimension of at least 80 nanometers.
18. The apparatus of claim 16 , wherein at least 50% of the additional portion of the tungsten has a grain size with a maximum dimension of at least 100 nanometers.
19. The apparatus of claim 15 , wherein the additional dielectric material has a dielectric constant at least equal to a dielectric constant of an aluminum oxide.
20. The apparatus of claim 15 , wherein the additional dielectric material includes hafnium oxide.
21. The apparatus of claim 15 , wherein the additional dielectric material includes hafnium silicate.
22. The apparatus of claim 15 , wherein the additional dielectric material includes titanium silicon nitride.