Silicon Nitride Plasma CVD TimeDomain CVD Plasma-enhanced CVD of Silicon Nitride Plasma enhanced techniques are often employed to deposit silicon nitride, since unlike silicon dioxide there are no thermal approaches which operate below 600 C. Deposition is usually performed in showerhead configuration reactors, operating at from a few hundred mTorr to a few Torr. Temperatures of 250 to 400 C are typically employed.
Ammonia is the most common oxidant, although pure nitrogen is also used.
Chemistry At low power density and low ammonia concentrations, the gas phase is dominated by SiH2, SiH3, and polymerized silanes. In this case, nitrogen must be added at the surface. Films produced under these conditions have copious Si-H and are relatively poor insulators. The conditions of the reactor can be easily diagnosed by monitoring the Si2H6 signal in the exhaust by mass spectroscopy. The same technique can be used with N2O or N2 as oxidants.