Pentachlorodisilane

1. A method of forming a silicon-containing film on a substrate, the method comprising subjecting a vapor of a silicon precursor consisting of pentachlorodisilane, and a nitrogen precursor comprising N and H atoms or an oxygen precursor to deposition conditions in the presence of the substrate so as to form a silicon-containing film on the substrate, wherein the silicon-containing film comprises a silicon nitrogen film or a silicon oxygen film, wherein the method uses atomic layer deposition, wherein the deposition conditions comprise a temperature from 200° C. to 700° C., a pressure from 0.1 Torr to 100 Torr for pentachlorodisilane, an exposure time of from 0.1 to 100 seconds per cycle for pentachlorodisilane, a film growth rate per cycle from 0.1 to 2.0 Angstroms, and wherein the silicon nitrogen film has a refractive index from 1.8 to 2.2 and the silicon oxygen film has a refractive index from 1.3 to 1.5, and wherein the silicon-containing film has a thickness from 1 nanometer to 50 nanometers.

2. The method of claim 1 , wherein the atomic layer deposition is plasma enhanced atomic layer deposition, wherein the plasma is ammonia plasma in nitrogen or argon or wherein the plasma is forming gas, or oxygen plasma, and wherein the plasma power is from 10 W to 100 W.

3. The method of claim 1 wherein the substrate is a semiconductor material.

4. The method of claim 1 , wherein the deposition is thermal atomic layer deposition.

5. The method of claim 1 comprising subjecting a first vapor of the silicon precursor and a second vapor of the nitrogen precursor, wherein the nitrogen precursor comprises ammonia, amine, hydrazine, or a combination of any two or three thereof, to deposition conditions in the presence of the substrate so as to form the silicon-containing film on the substrate, wherein the silicon-containing film is the silicon nitrogen film.

6. The method of claim 1 comprising subjecting a first vapor of the silicon precursor and a second vapor of the oxygen precursor, wherein the oxygen precursor comprises molecular oxygen, ozone, nitrous oxide, nitric oxide, nitrogen dioxide, water, hydrogen peroxide, or a combination of any two or three thereof, to deposition conditions in the presence of the substrate so as to form the silicon-containing film on the substrate, wherein the silicon-containing film is the silicon oxygen film.

7. The method of claim 5 or 6 , wherein the substrate is heated and disposed in a deposition reactor that is configured for atomic layer deposition, the method comprising repeatedly feeding the first vapor of the silicon precursor, purging with an inert gas, feeding the second vapor into the deposition reactor, and purging with an inert gas so as to form the silicon-containing film on the heated substrate, wherein the feeds may be the same or different.

8. The method of claim 6 , wherein the vapor deposition conditions lack carbon and oxygen and the silicon nitrogen film comprises a silicon nitride film.