Silicon particles are to be grown on Si seed crystals by chemical deposition of silane with \text { a rate } r^{\prime \prime}=k^{H} C_{S i H_{4}} \text {. If } \mathrm{T}=200^{\circ} \mathrm{C}, \mathrm{P}_{\mathrm{SH} 4}=0.1 \mathrm{~atm} \text {, and } k^{\prime \prime}=10 \mathrm{~cm} / \mathrm{min} \text {, } (1) calculate the time necessary to grow Si particles from 1 to 10 µm, assuming particles are spherical and that the reaction is reaction limited. The density of Si is2.33 g/cm and its molecular weight is 32. (2) Calculate the time to form these particles assuming that the process is mass transfer limited with DA -0.1 cm/sec = 6 cm/min.

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