3 SiH₂Cl₂    +     4 NH₃    →    Si₃N₄     +    6 HCl    +     6 H₂

For this furnace, there are two kinds of recipes: stoichiometric and low-stress.

The stoiciometric film is targeted to be true Si₃N₄, which is charachterised by refractive index that shold be 2.023 at 632.8 nm. Unfortunately, this film will have a large tensile stress, making it useless for membranes 

Low stress nitide is accomplished by decreasing the NH₃/SiH₂Cl₂ gaseous ratio thereby depositing silicon-rich silicon nitride SiN_x.

The SiH₂Cl₂ cylinder is placed in a cabinet at the back of the furnace, while the NH₃, a house gas, is stored in the inner left corner of the leftmost container at the gable end of the clean room. Detailed instruction on how to change gas cylinder is to be found in the NH₃ cas cabinet.

The SiH₂Cl₂ has an pneumatic interlock at the back of the furnece, while the NH₃ has its interlock in the visitor's corridor at the gable end of the clean room. These have to be re-activated after any power failure.

Settings for Pirani pressure gauges, in Torr:

3VS SP1=5.0, SP2=2.2·10^-1, SP3=2.0

4VS SP1=10, SP2=5.0, SP3=NA

Instructors

Licensed Users