Method of forming dielectric layers on a substrate and apparatus therefor
Methods of forming dielectric layers on a substrate comprising silicon and oxygen are disclosed herein. In some embodiments, a method of forming a dielectric layer on a substrate includes provide a substrate having an exposed silicon oxide layer; treating an upper surface of the silicon oxide layer with a plasma; and depositing a silicon nitride layer on the treated silicon oxide layer via atomic layer deposition. The silicon nitride layer may be exposed to a plasma nitridation process. The silicon oxide and silicon nitride layers may be subsequently thermally annealed. The dielectric layers may be used as part of a gate structure.
1. A method of forming a dielectric layer on a substrate, comprising:
providing a substrate having an exposed silicon oxide layer;
treating an upper surface of the silicon oxide layer with a plasma;
depositing a silicon nitride layer on the treated silicon oxide layer via atomic layer deposition at a temperature from about 300 degrees Celsius to about 700 degrees Celsius; and
exposing the silicon nitride layer to a second plasma.
2. The method of claim 1 , wherein providing a substrate having an exposed silicon oxide layer comprises:
forming a silicon oxide layer on the substrate by annealing the substrate in an oxidizing atmosphere.
3. The method of claim 1 , wherein treating an upper surface of the silicon oxide layer with a plasma comprises:
exposing the upper surface of the silicon oxide layer to a plasma comprising nitrogen.
4. The method of claim 1 , wherein treating an upper surface of the silicon oxide layer with a plasma comprises:
exposing the upper surface of the silicon oxide layer to a plasma comprising an inert gas.
5. The method of claim 1 , wherein treating an upper surface of the silicon oxide layer with a plasma comprises:
exposing the upper surface of the silicon oxide layer to a plasma formed by a power supply operating in a pulsed wave mode and having a duty cycle as low as about 5 percent.
6. The method of claim 1 , wherein the silicon nitride layer is deposited to a thickness of less than about 80 Å.
7. The method of claim 1 , wherein the silicon nitride layer is deposited to a thickness of less than about 20 Å.
8. The method of claim 1 , wherein the second plasma comprises nitrogen.
9. The method of claim 1 , wherein the second plasma comprises an inert gas.
10. The method of claim 1 , further comprising:
thermally annealing the silicon oxide and silicon nitride layers.
11. The method of claim 1 , wherein treating an upper surface of the silicon oxide layer with a plasma comprises:
exposing the upper surface of the silicon oxide layer to a non-nitrogen containing plasma comprising an inert gas.
12. The method of claim 2 , further comprising:
removing a native oxide from the substrate before forming the silicon oxide layer.
13. The method of claim 3 , wherein the plasma further comprises an inert gas.
14. The method of claim 5 , wherein the power supply provides power at a pulse frequency of about 10 kHz.
15. The method of claim 11 , wherein the inert gas comprises one or more of argon (Ar), helium (He), krypton (Kr), neon (Ne), or xenon (Xe).
16. A method of forming a dielectric layer on a substrate, comprising:
providing a substrate comprising silicon;
forming a silicon oxide layer on the substrate by annealing the substrate in an oxidizing atmosphere;
treating an upper surface of the silicon oxide layer with a plasma;
depositing a silicon nitride layer on the treated silicon oxide layer via atomic layer deposition at a temperature from about 300 degrees Celsius to about 700 degrees Celsius;
exposing the silicon nitride layer to a plasma; and
thermally annealing the silicon oxide and silicon nitride layers.
17. A method of forming a gate structure on a substrate, comprising:
providing substrate having an exposed silicon oxide layer;
treating an upper surface of the silicon oxide layer with a plasma;
depositing a silicon nitride layer on the silicon oxide layer via atomic layer deposition at a temperature from about 300 degrees Celsius to about 700 degrees Celsius;
exposing the silicon nitride layer to a plasma comprising at least one of nitrogen (N 2 ), ammonia (NH 3 ), argon (Ar), helium (He), krypton (Kr), neon (Ne), or xenon (Xe); and
forming a gate electrode layer above the silicon nitride layer.
18. The method of claim 17 , wherein providing a substrate having an exposed silicon oxide layer comprises:
forming a silicon oxide layer on the substrate by annealing the substrate in an oxidizing atmosphere.
19. The method of claim 17 , wherein treating an upper surface of the silicon oxide layer with a plasma comprises:
exposing the upper surface of the silicon oxide layer to a plasma comprising at least one of nitrogen (N 2 ), ammonia (NH 3 ), argon (Ar), helium (He), krypton (Kr), neon (Ne), or xenon (Xe).
20. The method of claim 17 , further comprising:
thermally annealing the silicon oxide and silicon nitride layers.
21. The method of claim 17 , further comprising:
forming a layer disposed between the silicon nitride layer and the gate electrode layer, the layer comprising at least two of silicon, oxygen, or aluminum.
22. The method of claim 17 , wherein the gate electrode layer comprises polysilicon or tantalum.