A recent study of the chemical vapor deposition of silica from silane (SiH4)  is believed...

A recent study of the chemical vapor deposition of silica from silane (SiH4)  is believed to proceed by the following irreversible two-step mechanism [J. Electrochem. Soc. , 139(9), 2659 ( 1992)]:

SiH4 + S  SiH2 •S + H2 (1)

SiH2 •S  Si + H2 (2)

This mechanism is somewhat different in that while SiH2 is irreversibly adsorbed, it is highly reactive. In fact, adsorbed SiH2 reacts as fast as it is formed [i.e., r*siH2.S= 0, i.e., PSSH (Chapter 7)], so that it can be assumed to behave as an active intermediate.

(a) Determine if this mechanism is consistent with the following data:

Deposition Rate (mm/min)	0.25	0.5	0.75	0.80
Silane Pressure (mtorr)	5	15	40	60

(b) At what partial pressures of silane would you take the next two data points?