Semiconductor and semiconductor manufacturing arrangements having a chalcogenide layer formed of columnar crystal grains perpendicular to a main substrate surface
View Patent ↗The annealing process at 400° C. or more required for the wiring process for a phase change memory has posed the problem in that the crystal grains in a chalcogenide material grow in an oblique direction to cause voids in a storage layer. The voids, in turn, cause peeling due to a decrease in adhesion, variations in resistance due to improper contact with a plug, and other undesirable events. After the chalcogenide material has been formed in an amorphous phase, post-annealing is conducted to form a (111)-oriented and columnarly structured face-centered cubic. This is further followed by high-temperature annealing to form a columnar, hexagonal closest-packed crystal. Use of this procedure makes it possible to suppress the growth of inclined crystal grains that causes voids, since crystal grains are formed in a direction perpendicular to the surface of an associated substrate.
1. A semiconductor device comprising:
a semiconductor substrate;
a select element on a main surface of the semiconductor substrate;
an interlayer dielectric film provided over said select element;
a plug provided so as to penetrate through said interlayer dielectric film, said plug being electrically connected to said select element; and
a storage layer provided on an upper surface of said interlayer dielectric film and on an upper surface of said plug and able to store information via an atomic arrangement change, inclusive of a reversible phase change, between a crystal phase and an amorphous phase;
wherein the storage layer is a chalcogenide layer of columnar chalcogenide crystal grains predominantly-oriented in a direction perpendicular to the main surface of the semiconductor substrate;
wherein a crystal system of the columnar chalcogenide crystal grains is hexagonal.
2. The semiconductor device according to claim 1 , wherein the chalcogenide layer is such that a number of the columnar chalcogenide crystal grains predominantly-oriented in a direction perpendicular to the main surface of the semiconductor substrate is at least four times a number of inclined crystal grains oriented in a direction oblique to the main surface of the semiconductor surface.
3. The semiconductor device according to claim 1 , wherein the chalcogenide layer is such that a hexagonal (001) crystal face and crystal faces other than (001) are each oriented in a direction horizontal to the main surface of the semiconductor surface.
4. The semiconductor device according to claim 1 , wherein the chalcogenide layer contains at least two elements selected from the group consisting of Ge, Sb, and Te.
5. The semiconductor device according to claim 1 , wherein the chalcogenide layer contains at least two elements selected from the group consisting of Ge, Sb, and Te; and at least one element selected from the group consisting of a group-2b element, a group-1b element, an element of groups 3a to 7a, and a group-8 element in the periodic table.
6. The semiconductor device according to claim 1 , wherein the chalcogenide layer has the columnar chalcogenide crystal grains predominantly-oriented in the direction perpendicular to the main surface of the semiconductor substrate existing in at least 80 percentage of all crystal grains in the chalcogenide layer.
7. A semiconductor device comprising:
a semiconductor substrate;
a select element on a main surface of the semiconductor substrate;
an interlayer dielectric film provided over said select element;
a plug provided so as to penetrate through said interlayer dielectric film, said plug being electrically connected to said select element; and
a storage layer provided on an upper surface of said interlayer dielectric film and on an upper surface of said plug and able to store information via an atomic arrangement change, inclusive of a reversible phase change, between a crystal phase and an amorphous phase;
wherein the storage layer is an unused original-manufacturer chalcogenide layer of columnar chalcogenide crystal grains predominantly-oriented in a direction perpendicular to the main surface of the semiconductor substrate, where the chalcogenide layer is unused in that such chalcogenide layer has not yet been recorded on by any user of the semiconductor device;
wherein a crystal system of the columnar chalcogenide crystal grains is hexagonal.
8. The semiconductor device according to claim 7 , wherein the chalcogenide layer is such that a number of the columnar chalcogenide crystal grains predominantly-oriented in a direction perpendicular to the main surface of the semiconductor substrate is at least four times a number of inclined crystal grains oriented in a direction oblique to the main surface of the semiconductor surface.
9. The semiconductor device according to claim 7 , wherein the chalcogenide layer has the columnar chalcogenide crystal grains predominantly-oriented in the direction perpendicular to the main surface of the semiconductor substrate existing in at least 80 percentage of all crystal grains in the chalcogenide layer.
10. The semiconductor device according to claim 7 , wherein the chalcogenide layer is such that a hexagonal (001) crystal face and crystal faces other than (001) are each oriented in a direction horizontal to the main surface of the semiconductor surface.
11. The semiconductor device according to claim 7 , wherein the chalcogenide layer contains at least two elements selected from the group consisting of Ge, Sb, and Te.
12. The semiconductor device according to claim 7 , wherein the chalcogenide layer contains at least two elements selected from the group consisting of Ge, Sb, and Te; and at least one element selected from the group consisting of a group-2b element, a group-1b element, an element of groups 3a to 7a, and a group-8 element in the periodic table.
13. A semiconductor device comprising:
a semiconductor substrate;
a select element on a main surface of the semiconductor substrate; an interlayer dielectric film provided over said select element;
a plug provided so as to penetrate through said interlayer dielectric film, said plug being electrically connected to said select element; and
a storage layer provided on an upper surface of said interlayer dielectric film and on an upper surface of said plug and able to store information via an atomic arrangement change, inclusive of a reversible phase change, between a crystal phase and an amorphous phase;
wherein the storage layer is a chalcogenide layer in existence before any user recording operation to record information in the chalcogenide layer, of columnar chalcogenide crystal grains predominantly-oriented in a direction perpendicular to the main surface of the semiconductor substrate;
wherein a crystal system of the columnar chalcogenide crystal grains is hexagonal.
14. The semiconductor device according to claim 13 , wherein the chalcogenide layer is such that a number of the columnar chalcogenide crystal grains predominantly-oriented in a direction perpendicular to the main surface of the semiconductor substrate is at least four times a number of inclined crystal grains oriented in a direction oblique to the main surface of the semiconductor surface.
15. The semiconductor device according to claim 13 , wherein the chalcogenide layer has the columnar chalcogenide crystal grains predominantly-oriented in the direction perpendicular to the main surface of the semiconductor substrate existing in at least 80 percentage of all crystal grains in the chalcogenide layer.
16. The semiconductor device according to claim 13 , wherein the chalcogenide layer is such that a hexagonal (001) crystal face and crystal faces other than (001) are each oriented in a direction horizontal to the main surface of the semiconductor surface.
17. The semiconductor device according to claim 13 , wherein the chalcogenide layer contains at least two elements selected from the group consisting of Ge, Sb, and Te.
18. The semiconductor device according to claim 13 , wherein the chalcogenide layer contains at least two elements selected from the group consisting of Ge, Sb, and Te; and at least one element selected from the group consisting of a group-2b element, a group-1b element, an element of groups 3a to 7a, and a group-8 element in the periodic table.
19. A semiconductor device comprising:
a semiconductor substrate;
a select element on a main surface of the semiconductor substrate;
an interlayer dielectric film provided over said select element;
a plug provided so as to penetrate through said interlayer dielectric film, said plug being electrically connected to said select element; and
a storage layer provided on an upper surface of said interlayer dielectric film and on an upper surface of said plug and able to store information via an atomic arrangement change, inclusive of a reversible phase change, between a crystal phase and an amorphous phase;
wherein the storage layer is a chalcogenide layer of columnar chalcogenide crystal grains, wherein a majority of the columnar chalcogenide crystal grains are oriented in a direction perpendicular to the main surface of the semiconductor substrate;
wherein a crystal system of the columnar chalcogenide crystal grains is hexagonal.