Artificial synapse with hafnium oxide-based ferroelectric layer in CMOS front-end
Artificial synaptic devices with a HfO 2 -based ferroelectric layer that can be implemented in the CMOS front-end are provided. In one aspect, a method of forming a FET device is provided. The method includes: forming a shallow STI region in a substrate separating a first active area of the substrate from a second active area of the substrate; forming at least one FeFET on the substrate in the first active area having a ferroelectric material including a HfO 2 -based material; and forming at least one logic FET alongside the at least one FeFET on the substrate in the second active area, wherein the at least one logic FET has a gate dielectric including the HfO 2 -based material. A FET device formed by the present techniques is also provided.
1. A method of forming a field-effect transistor (FET) device, the method comprising the steps of:
forming a shallow trench isolation (STI) region in a substrate separating a first active area of the substrate from a second active area of the substrate;
forming at least one ferroelectric FET (FeFET) on the substrate in the first active area having a ferroelectric material comprising a first hafnium oxide (HfO 2 )-based material; and
forming at least one logic FET alongside the at least one FeFET on the substrate in the second active area, wherein the at least one logic FET has a gate dielectric comprising a second HfO 2 -based material that is different from the first HfO 2 -based material, wherein the method further comprises the steps of:
depositing a dielectric capping layer on the first HfO 2 -based material in the first active area and on the second HfO 2 -based material in the second active area;
depositing a metal layer onto the dielectric capping layer in both the first active area and the second active area;
patterning the first HfO 2 -based material, dielectric capping layer and the metal layer into the at least one FeFET on the substrate in the first active area; and
annealing both the at least one FeFET and the at least one logic FET.
2. The method of claim 1 , wherein the substrate is doped with an n-type or p-type dopant.
3. The method of claim 1 , wherein the ferroelectric material comprising the first HfO 2 -based material has a thickness T 1 , wherein the gate dielectric comprising the second HfO 2 -based material has a thickness T 2 , and wherein T 1 >T 2 .
4. The method of claim 1 , wherein the first HfO 2 -based material comprises a first material selected from the group consisting of: pure HfO 2 , Hf ˜0.5 Zr ˜0.5 O 2 , doped HfO 2 , and combinations thereof, and wherein the second HfO 2 -based material comprises a second different material selected from the group consisting of: pure HfO 2 , Hf ˜0.5 Zr ˜0.5 O 2 , doped HfO 2 , and combinations thereof.
5. The method of claim 4 , wherein the doped HfO 2 comprises a dopant selected from the group consisting of: nitrogen (N), carbon (C), silicon (Si), aluminum (Al), lanthanum (La), gadolinium (Gd), yttrium (Y), scandium (Sc), strontium (Sr), and combinations thereof, and combinations thereof.
6. The method of claim 1 , wherein the dielectric capping layer comprises a material selected from the group consisting of: lanthanum oxide (La 2 O 3 ), aluminum oxide (Al 2 O 3 ), and combinations thereof.
7. The method of claim 1 , wherein the metal layer comprises a material selected from the group consisting of: titanium nitride (TiN), tantalum nitride (TaN), and combinations thereof.
8. The method of claim 1 , further comprising the steps of:
covering the at least one FeFET with a mask;
depositing an additional dielectric capping layer onto the metal layer in the second active area;
depositing an additional metal layer onto the additional dielectric capping layer in the second active area; and
patterning the second HfO 2 -based material, dielectric capping layer, the metal layer, the additional dielectric capping layer and the additional metal layer into the at least one logic FET on the substrate in the second active area.
9. The method of claim 8 , wherein the additional dielectric capping layer comprises a material selected from the group consisting of: La 2 O 3 , Al 2 O 3 and combinations thereof.
10. The method of claim 8 , wherein the additional metal layer comprises a metal selected from the group consisting of: TiN, TaN, and combinations thereof.
11. The method of claim 1 , wherein the at least one FeFET and the at least one logic FET are annealed at a temperature of from about 800° C. to about 1200° C., and ranges therebetween.
12. The method of claim 1 , wherein the at least one FeFET and the at least one logic FET are annealed at a temperature of from about 1000° C. to about 1200° C., and ranges therebetween.
13. A method of forming a FET device, the method comprising the steps of:
forming a STI region in a substrate separating a first active area of the substrate from a second active area of the substrate;
forming at least one FeFET on the substrate in the first active area having a ferroelectric material comprising a first HfO 2 -based material; and
forming at least one logic FET alongside the at least one FeFET on the substrate in the second active area, wherein the at least one logic FET has a gate dielectric comprising a second HfO 2 -based material, wherein the ferroelectric material comprising the first HfO 2 -based material has a thickness T 1 , wherein the gate dielectric comprising the second HfO 2 -based material has a thickness T 2 , and wherein T 1 >T 2 , wherein the method further comprises the steps of:
depositing a dielectric capping layer on the first HfO 2 -based material in the first active area and on the second HfO 2 -based material in the second active area;
depositing a metal layer onto the dielectric capping layer in both the first active area and the second active area;
patterning the first HfO 2 -based material, dielectric capping layer and the metal layer into the at least one FeFET on the substrate in the first active area; and
annealing both the at least one FeFET and the at least one logic FET.
14. The method of claim 13 , wherein the first HfO 2 -based material comprises a first material selected from the group consisting of: pure HfO 2 , Hf ˜0.5 Zr ˜0.5 O 2 , doped HfO 2 , and combinations thereof, and wherein the second HfO 2 -based material comprises a second different material selected from the group consisting of: pure HfO 2 , Hf ˜0.5 Zr ˜0.5 O 2 , doped HfO 2 , and combinations thereof.
15. The method of claim 14 , wherein the doped HfO 2 comprises a dopant selected from the group consisting of: nitrogen (N), carbon (C), silicon (Si), aluminum (Al), lanthanum (La), gadolinium (Gd), yttrium (Y), scandium (Sc), strontium (Sr), and combinations thereof, and combinations thereof.
16. The method of claim 13 , wherein the dielectric capping layer comprises a material selected from the group consisting of: La 2 O 3 , Al 2 O 3 , and combinations thereof.
17. The method of claim 13 , wherein the metal layer comprises a material selected from the group consisting of: TiN, TaN, and combinations thereof.
18. The method of claim 13 , further comprising the steps of:
covering the at least one FeFET with a mask;
depositing an additional dielectric capping layer onto the metal layer in the second active area;
depositing an additional metal layer onto the additional dielectric capping layer in the second active area; and
patterning the second HfO 2 -based material, dielectric capping layer, the metal layer, the additional dielectric capping layer and the additional metal layer into the at least one logic FET on the substrate in the second active area.