Switch device and storage unit having a switch layer between first and second electrodes
View Patent ↗A switch device includes: a first electrode; a second electrode disposed to oppose the first electrode; a switch layer provided between the first electrode and the second electrode, and including at least one or more kinds of chalcogen elements and one or more kinds of first elements out of the one or more kinds of chalcogen elements, the one or more kinds of first elements, and a second element including one or both of oxygen (O) and nitrogen (N), the one or more kinds of chalcogen elements being selected from tellurium (Te), selenium (Se), and sulfur (S), and the one or more kinds of first elements being selected from boron (B), carbon (C), and silicon (Si).
1. A switch device comprising:
a first electrode;
a second electrode disposed to oppose the first electrode; and
a switch layer provided between the first electrode and the second electrode, the switch layer comprising:
one or more kinds of chalcogen elements selected from tellurium (Te), selenium (Se), and sulfur (S); and
one or more kinds of first elements, the one or more kinds of first elements being selected from magnesium (Mg), calcium (Ca), and strontium (Sr).
2. The switch device according to claim 1 , wherein the switch layer further comprises one or both of nitrogen (N) and oxygen (O).
3. The switch device according to claim 1 , wherein the switch layer further comprises one or more of nitrogen (N) and oxygen (O), wherein the one or more of N and O is within a range of 5% to 25% both inclusive.
4. The switch device according to claim 1 , wherein, without a phase change between an amorphous phase and a crystalline phase, the switch layer is turned to a low-resistance state by setting an applied voltage to a predetermined threshold voltage or higher, and is turned to a high-resistance state by decreasing the applied voltage to the threshold voltage or lower.
5. The switch device according to claim 1 , wherein the switch layer comprises one of compositions including BTe, CTe, BCTe, CSiTe, BSiTe, BCSiTe, BTeN, CTeN, BCTeN, CSiTeN, BSiTeN, BCSiTeN, BTeO, CTeO, BCTeO, CSiTeO, BSiTeO, BCSiTeO, BTeON, CTeON, BCTeON, CSiTeON, BSiTeON, and BCSiTeON.
6. The switch device according to claim 1 , wherein the switch layer has a composition ratio (%) of (BuTex)OyNz (where 30≤u≤90%, 10≤x≤70%, 0≤y≤35%, and 0≤z≤40% or 0≤y+z≤40%).
7. The switch device according to claim 1 , wherein the switch layer has a composition ratio (%) of (CvTex)OyNz (where 30≤v≤60%, 40≤x≤70%, 0≤y≤15%, and 0≤z≤20% or 0≤y+z≤20%).
8. The switch device according to claim 1 , wherein the switch layer has a composition ratio (%) of (BuCvTex)OyNz (where 10≤u≤90%, 0≤v≤65%, 0≤x≤70%, 0≤y≤35%, and 0≤z≤40% (where 30≤u+v≤90% and 0≤y+z≤40%)).
9. The switch device according to claim 1 , wherein the switch layer has a composition ratio (%) of (CvSiwTex)OyNz (where 10≤v≤65%, 10≤w≤80%, 20≤x≤70%, 0≤y≤35%, and 0≤y≤40% (where 30≤v+w≤80% and 0≤y+z≤40%)).
10. The switch device according to claim 1 , wherein the switch layer has a composition ratio (%) of (BuSiwTex)OyNz (where 10≤u≤90%, 0≤w≤65%, 10≤x≤70%, 0≤y≤35%, and 0≤z≤40% (where 30≤u+w≤90% and 0≤y+z≤40%)).
11. The switch device according to claim 1 , wherein the switch layer has a composition ratio (%) of (BuCvSiwTex)OyNz (where 0≤u≤90%, 0≤v≤65%, 10≤w≤65%, 10≤x≤70%, 0≤y≤35%, and 0≤z≤40% (where 30≤u+v+w≤90% and 0≤y+z≤40%)).
12. The switch device according to claim 1 , wherein the switch layer has a composition ratio (%) of (BuCvSiwZx)OyNz (where 20≤x≤50%, 40≤u+v+w≤60%, 5≤y≤25%, 5≤z≤25%, and 5≤y+z≤25% (where Z=(Te, Se, S))).
13. The switch device according to claim 1 , wherein the switch layer further comprises one or more kinds selected from aluminum (Al), and gallium (Ga).
14. The switch device according to claim 13 , wherein the switch layer has a composition ratio (%) of (MtBuCvSiwTex)OyNz (where 0≤t≤30%, 40≤u+v+w≤90%, 10≤x≤50%, 5≤y≤25%, and 5≤z≤25%, where a composition ratio of O and N is 5≤y+z≤25% (where M=Mg, Zn, Ca, Sr, Al, Ga)).
15. The switch device according to claim 13 , wherein the switch layer has a composition ratio of (MtBuCvSiwZx)OyNz (where 0≤t≤30%, 10≤x≤50%, 40≤u+v+w≤90%, 5≤y≤25%, and 5≤z≤25%, where a composition ratio of O and N is 5≤y+z≤25 (where M=(Mg, Zn, Ca, Sr, Al, Ga) and Z=(Te, Se, and S))).
16. The switch device according to claim 1 , wherein the switch layer comprises a high-resistance layer on one or both of a surface on the first electrode side and a surface on the second electrode side.
17. The switch device according to claim 16 , wherein the high-resistance layer includes one or more kinds selected from oxides, nitrides, and oxynitrides of aluminum (Al), silicon (Si), magnesium (Mg), hafnium (Hf), and rare-earth metal elements.
18. The switch device according to claim 1 , wherein a thickness of the switch layer is within a range of 5 nm to 100 nm both inclusive.
19. A storage unit provided with a plurality of memory cells, the memory cells each including a storage device and a switch device directly coupled to the storage device, the switch device comprising:
a first electrode;
a second electrode disposed to oppose the first electrode; and
a switch layer provided between the first electrode and the second electrode, the switch layer comprising:
one or more kinds of chalcogen elements, the one or more kinds of chalcogen elements being selected from tellurium (Te), selenium (Se), and sulfur (S); and
one or more kinds of first elements, the one or more kinds of first elements being selected from magnesium (Mg), calcium (Ca), and strontium (Sr).
20. The storage unit according to claim 19 , wherein the storage device includes a storage layer between the first electrode and the second electrode of the switch device.
21. The storage unit according to claim 20 , wherein the storage layer includes a ion source layer and a resistance change layer, the ion source layer including one or more kinds of chalcogen elements selected from tellurium (Te), sulfur (S), and selenium (Se).
22. The storage unit according to claim 20 , wherein the storage layer and the switch layer are stacked with a third electrode in between the first electrode and second electrode.
23. The storage unit according to claim 20 , wherein the storage layer and the switch layer are stacked with a resistance change layer in between.
24. The storage unit according to claim 20 , wherein the switch device includes a high-resistance layer on one or both of a surface on the first electrode side and a surface on the second electrode side, and the storage layer and the switch layer are stacked with the high-resistance layer in between.
25. The storage unit according to claim 20 , wherein a high-resistance layer of the switch layer also serves as a resistance change layer of the storage layer.
26. The storage unit according to claim 19 , wherein a plurality of row lines and a plurality of column lines are included, and the memory cells are each provided around corresponding one of intersection regions of the row lines and the column lines.
27. The storage unit according to claim 20 , wherein the storage layer is configured of one of a resistance-change layer made of a transition metal oxide, a phase-change memory layer, and a magnetoresistance-change memory layer.
28. A switch device comprising:
a first electrode;
a second electrode disposed to oppose the first electrode; and
a switch layer provided between the first electrode and the second electrode, the switch layer comprising:
one or more kinds of chalcogen elements selected from tellurium (Te), selenium (Se), and sulfur (S); and
a compound having a band gap of 2.2 V or higher, the compound comprising one or more of magnesium (Mg), calcium (Ca), and strontium (Sr).