A chemical vapor deposition $($CVD$)$ process is used to deposit pure silicon thin films on wafers for electronic device applications.

One way to deposit pure silicon onto a surface is by the heterogeneous surface reaction:

$SiHC{l}_3(g)+H_2(g)Si(s)+3HCl(g)$

In the present process, $1\mathrm{.}0$mole$\%$ trichlorosilane

$(SiHC{l}_3)$ vapor $($species $\{$:$A)$ diluted in $H_2$ gas $($species

$B)$ is fed to the CVD reactor shown in Figure $28\mathrm{.}6$ to

establish a bulk velocity of $200c\frac{m}{s}.$ The trichlorosilane

is reduced by the $H_2$ gas to elemental silicon solid $(Si),$

which is deposited as a thin film on a $15cm$ by $15cm$

wafer. Although the reaction produces $HCl$ gas, it is

significantly diluted by the $H_2$ gas, and so the $H_2$ gas

can also be considered as the carrier gas. The flow over the

silicon wafer is approximated as flow over a flat plate.

The reaction process is maintained at $1\mathrm{.}0$atm and $1200K.$

The reactor contains elaborate safety systems to

handle the toxic and flammable gases. At $1200K,$ the

surface reaction constant for the first$-$order decomposi$-$

tion reaction with respect to $SiHC{l}_3$ vapor concentration

is $k_{{?}_{?}}(s)=0\mathrm{.}83c\frac{m}{s},$ with the surface reaction rate law

defined as $R_{A,s}^{\text{'}}=-k_s{c}_{As},$ based on the studies of Stein. ${?}^3$

defined as $R_{A,s}^{\text{'}}=-k_s{c}_{As},$ based on the studies of Stein. ${?}^3$