Methods of forming silicon nitride layers using nitrogenous compositions
The present invention provides nitrogenous compositions for forming a silicon nitride layer, wherein the nitrogenous composition comprises a hydrazine compound, an amine compound or a mixture thereof. The present invention further provides source compositions for forming a silicon nitride layer, wherein the source composition comprises a nitrogenous composition comprising a hydrazine compound, an amine compound or a mixture thereof, and a silicon source comprising hexachlorodisilane. Methods for forming silicon nitride layers are further provided. The silicon nitride layers provided herein may be formed on a substrate at a low temperature and may further exhibit improved breakdown voltage and an enhanced etch resistance.
1. A method for forming a silicon nitride layer comprising:
introducing a silicon source comprising hexachlorodisilane into a reactor to chemically react at least a portion of the silicon source with a surface of a substrate;
introducing a first purge gas into the reactor to remove an unreacted silicon source from the substrate;
introducing an activated nitrogenous compound into the reactor to form a silicon nitride layer on the substrate by chemically reacting the activated nitrogenous compound with the chemically reacted silicon source, wherein the activated nitrogenous compound comprises a hydrazine compound, an amine compound or mixture thereof; and
introducing a second purge gas into the reactor to remove an unreacted activated nitrogenous compound from the substrate, wherein the silicon nitride layer has a refractive index in a range of about 1.7 to about 2.3.
2. The method of claim 1 , wherein introducing the silicon source, introducing the first purge gas, introducing the activated nitrogenous compound and introducing the second purge gas are performed repeatedly.
3. The method of claim 2 , wherein performing one cycle of introducing the silicon source, introducing the first purge gas, introducing the activated nitrogenous compound and introducing the second purge gas produces a silicon nitride layer having a thickness of about 0.5 Å to about 30 Å.
4. The method of claim 1 , wherein introducing the silicon source, introducing the first purge gas, introducing the activated nitrogenous compound and introducing the second purge gas are performed at a temperature less than about 600° C.
5. The method of claim 1 , wherein the reactor comprises a chemical vapor deposition chamber or an atomic layer deposition chamber.
6. The method of claim 1 , wherein the activated nitrogenous compound is formed using a direct plasma apparatus, a remote plasma apparatus or an ultraviolet ray.
7. The method of claim 1 , wherein the first and second purge gases comprise inactive gases, respectively.
8. The method of claim 1 , wherein the silicon nitride layer has a composition ratio between nitrogen and silicon of about 1 to about 1.6.
9. The method of claim 1 , wherein the silicon nitride layer has a higher etch resistance and/or a lower refractive index compared to a silicon nitride layer formed by a conventional method.
10. The method of claim 1 , wherein introducing the silicon source, introducing the first purge gas, introducing the activated nitrogenous compound and introducing the second purge gas are performed at a temperature in a range of about 300° C. to about 700° C.
11. The method of claim 1 , wherein introducing the silicon source, introducing the first purge gas, introducing the activated nitrogenous compound and introducing the second purge gas are performed under a pressure in a range of about 0.1Torr to about 10Torr.