Semiconductor device having hydrogen in a dielectric layer
Embodiment described herein provide a thermal treatment process following a high-pressure anneal process to keep hydrogen at an interface between a channel region and a gate dielectric layer in a field effect transistor while removing hydrogen from the bulk portion of the gate dielectric layer. The thermal treatment process can reduce the amount of threshold voltage shift caused by a high-pressure anneal. The high-pressure anneal and the thermal treatment process may be performed any time after formation of the gate dielectric layer, thus, causing no disruption to the existing process flow.
1. A structure comprising:
an active area on a substrate, the active area having a channel region;
a gate structure over the channel region of the active area, wherein the gate structure includes:
an interfacial layer over the active area;
a conformal dielectric layer over the interfacial layer; and
a gate electrode layer over the interfacial layer; and
wherein a ratio of a peak concentration of hydrogen in the interfacial layer to a peak concentration of hydrogen in the conformal dielectric layer is in a range from about 0.1 to about 5.
2. The structure of claim 1 , wherein the interfacial layer includes a native oxide, silicon oxide, silicon nitride, silicon oxynitride, or a combination thereof.
3. The structure of claim 1 , wherein the interfacial layer has a thickness in a range from greater than 0 nm to 5 nm.
4. The structure of claim 1 , wherein the conformal dielectric layer includes a high-k dielectric layer, a silicon oxide layer, a silicon oxynitride layer, a silicon nitride layer, or a combination thereof.
5. The structure of claim 1 , wherein the ratio of the peak concentration of hydrogen in the interfacial layer to the peak concentration of hydrogen in the conformal dielectric layer is in a range from about 2.7 to about 5.
6. The structure of claim 1 , wherein a ratio of a total hydrogen count in the interfacial layer to a total hydrogen count in the conformal dielectric layer is in a range from about 0.1 to about 2.
7. The structure of claim 1 , wherein hydrogen concentration in the conformal dielectric layer is higher at a location proximate to the interfacial layer than at a location distal from the interfacial layer.
8. The structure of claim 1 , wherein a peak concentration of hydrogen in the interfacial layer is greater than the peak concentration of hydrogen in the conformal dielectric layer.
9. A structure comprising:
source/drain regions in a substrate;
a channel region in the substrate, the channel region being interposed between the source/drain regions;
an interfacial layer over the channel region, the interfacial layer having a first peak concentration of hydrogen;
a gate dielectric layer over the interfacial layer, the gate dielectric layer comprising hydrogen, the gate dielectric layer having a second peak concentration of hydrogen, the first peak concentration of hydrogen being greater than the second peak concentration of hydrogen; and
a gate electrode over the gate dielectric layer.
10. The structure of claim 9 , wherein a total amount of hydrogen atoms in the gate dielectric layer is greater than a total amount of hydrogen atoms in the interfacial layer.
11. The structure of claim 10 , wherein a thickness of the gate dielectric layer is about 10 nm and a thickness of the interfacial layer is about 2.5 nm.
12. The structure of claim 9 , wherein a ratio of the first peak concentration of hydrogen to the second peak concentration of hydrogen is in a range from 2.7 to 5.
13. The structure of claim 9 , wherein the first peak concentration of hydrogen is at a location spaced apart from an interface between the interfacial layer and the gate dielectric layer.
14. The structure of claim 9 , wherein a thickness of the interfacial layer is greater than 0 nm to about 5.0 nm.
15. The structure of claim 14 , wherein a thickness of the gate dielectric layer is in a range from 1 nm to 10 nm.
16. A structure comprising:
source/drain regions in a substrate;
a channel region in the substrate, the channel region being interposed between the source/drain regions;
an interfacial layer over the channel region, the interfacial layer having a first peak concentration of hydrogen;
a gate dielectric layer over the interfacial layer, the gate dielectric layer having a second peak concentration of hydrogen, the first peak concentration of hydrogen being greater than the second peak concentration of hydrogen, wherein the first peak concentration of hydrogen in the interfacial layer is offset from an upper surface and a lower surface of the interfacial layer; and
a gate electrode over the gate dielectric layer.
17. The structure of claim 16 , wherein the gate dielectric layer comprises a metal oxide or a metal silicate.
18. The structure of claim 16 , wherein the interfacial layer includes a native oxide, silicon oxide, silicon nitride, silicon oxynitride, or a combination thereof.
19. The structure of claim 16 , wherein a ratio of the first peak concentration of hydrogen to the second peak concentration of hydrogen is in a range from 2.5 to 5.
20. The structure of claim 16 , wherein a total count of hydrogen atoms in the gate dielectric layer is about to 1.04×10 5 , wherein a total count of hydrogen atoms in the interfacial layer is about 9.63×10 4 .