The iodide process and the hydrogen reduction process of SiCl
4 have been investigated as methods for preparing high purity silicon. The reactions of these processes are both heterogeneous, taking place on a hot surface. In the iodide process, the amount of Si deposition through thermal decomposition of SiI
4 on the hot surface of an iodide cell consisting of a fused quartz tube was studied as a function of the four following operating variables: (a) the amount of iodine introduced in the cell, (b) the temperature of SiI
4, (c) the temperature of the decomposition furnace and (d) the thermal decomposition time. In the reduction process, the yield of Si deposition through the reduction of SiCl
4 by H
2 on the hot surface of quartz tube in the reduction cell was studied as a function of three variables: (a) the temperature of H
2-SiCl
4 mixing chamber, (b) the H
2 flow rate, and (c) the reduction temperature. The results of spectroscopic analysis of Si prepared by these processes are shown in Table 2. Si obtained by the reduction process show shigher purity than from the iodide process.
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