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Solar grade silicon is currently produced mainly through blending semiconductor grade silicon waste with metallurgical grade silicon. As the demand for solar cells continues to increase rapidly, soon demand will outstrip supply of semiconductor grade silicon waste. A process for producing solar grade silicon efficiently and without relying on other industries is needed. It is proposed to produce solar grade silicon of 6N purity (99.9999%) by reacting silicon tetrachloride with aluminum monochloride via the following reaction: 2 AlCl(g) + SiCl4(g)= Si(s) + 2 AlCl3(g) Aluminum monochloride is proposed as the reductant for silicon tetrachloride because it is an extremely strong reducing agent and the reaction will produce all gaseous by-products. Additionally, the aluminum trichloride produced can be recycled to form more aluminum monochloride, which is produced by reacting aluminum metal with aluminum trichloride in the following reaction: AlCl3(g) + 2 Al(l)= 3 AlCl(g) High yields of AlCl have only been found above 1200°C, with very little AlCl present in equilibrium with Al and AlCl3 at lower temperatures. The high temperatures under which AlCl can be found in larger quantities makes it difficult to determine if the AlCl3 reacting with Al is actually producing AlCl as opposed to another subhalide such as AlCl2. Numerous IR spectroscopy studies have been undertaken to confirm that the reaction of aluminum trichloride gas with molten aluminum does produce aluminum monochloride, with all such studies confirming that this theoretical path is correct. Unlike previous studies, which pass the AlCl3 gas over molten aluminum, it is proposed to bubble the AlCl3 gas into the molten aluminum. This should increase yield of aluminum monochloride, which was not a priority in previous studies. In order to achieve the project objectives a literature review of silicon manufacturing techniques as well as aluminum monochloride production was completed. Experiments to determine the rate of sublimation of aluminum trichloride were to be done in order to determine what temperature at which to sublime the aluminum trichloride. Aluminum trichloride was bubbled into aluminum metal to form aluminum monochloride with experimental conditions being varied to increase yield. Yield was determined through analysis of the reaction products, which was difficult due to the instability of aluminum monochloride, which dissociates at room temperature back into aluminum trichloride and aluminum metal. After the yield of aluminum monochloride was maximized, silicon tetrachloride was introduced into the reactor to react with the aluminum monochloride to form silicon metal. / Thesis (Master, Mining Engineering) -- Queen's University, 2011-09-18 18:16:36.31

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Some new inorganic and organometallic derivatives of methylcyclosiloxanes have been prepared and characterized by IR, MS and ('1)H NMR. Compounds, {CH(,3)(Br)SiO}(,3) and {CH(,3)(Br)SiO}(,4) were prepared by cleavage of silicon-phenyl bond with bromine at low temperature. The reaction of {CH(,3)(Br)SiO}(,3) with Na(sec-butyl)(,3)BH at low temperature produced the highly reactive trimer, {CH(,3)(H)SiO}(,3). Compounds {CH(,3)(Co(CO)(,4))SiO}(,4), {CH(,3)(Fe(CO)(,2)(eta)('5)-C(,5)H(,5))SiO}(,4), and {CH(,3)(Co(CO)(,4)SiO}(,5) were prepared by the hydrogen elimination reaction of {CH(,3)(H)SiO}(,n), n = 4 and 5 with Co(,2)(CO)(,8) and {Fe(CO)(,2)(eta)('5)-C(,5)H(,5)}(,2). It was also possible to isolate the compound {CH(,3)(Co(CO)(,4))SiO}(,1){CH(,3)(Fe(CO)(,2)(eta)('5)-C(,5)H(,5))SiO}(,3) by reacting {CH(,3)(H)SiO}(,1){CH(,3)(Fe(CO)(,2)(eta)('5)-C(,5)H(,5))SiO}(,3) with a stoichiometric amount of Co(,2)(CO)(,8). A detailed study of mass spectra of {CH(,3)(R)SiO}(,n), where R = H, (n = 4, 5, and 6), R = C(,6)H(,5), (n = 3 and 4), R = Br, (n = 3 and 4), R = Co(CO)(,4), (n = 4 and 5) and R = Fe(CO)(,2)(eta)('5)-C(,5)H(,5), (n = 4) was achieved. Compounds R = Co(CO)(,4) show stepwise loss of all CO groups from ions {M}('+(.)), {M-Co(CO)(,4)}('+), and also {M}('++). A simple empirical approach based on the chemical environment of methyl protons was used to assign ('1)H NMR spectra of geometric isomers of substituted methylcyclosiloxanes. The total assignment of ('1)H NMR spectra allowed the determination of the isomeric composition of most new compounds mentioned above.

<p>The growth of amorphous hydrogenated silicon (a-Si:H) thin films deposided by hot wire chemical vapor deposition (HWCVD) has been studied. The films have been characterised for optical and structural properties by means of UV/VIS,FITR,ERDA, XRD.XTEM and Raman spectroscopy. Low subtrate heater temperatures in the range form 130 to 200 degrees celcius were used in this thesis because it is believed to allow for the deposition of device quality a-Si:H which can be used for electronic photovoltaic devices. Furthermore, low temperatures allows the deposition of a-Si:H on any subtrate and thus offers the possibility of making large area devices on flexible organic substances. We showed that the optical and structural properties of grown a-Si:H films depended critically upon whether the films were produced with silane gas or silane diluted with hydrogen gas. We also showed that it is possible to to deposit crystalline materials at low temperature under high hydrogen dilution ratio of silane gas.</p>

To harness the wealth of success and computational power from the microelectronics industry, lab-on-a-chip (LOAC) applications should be fully integrated with silicon platforms. This works demonstrates a dielectrophoresis-based LOAC device built entirely on silicon using standard CMOS (complementary metal oxide semiconductor) processing techniques. The signal phases on multiple electrodes were controlled with only four electrical contacts, which connected to the device using three metal layers separated with interlayer dielectric. Indium tin oxide was deposited on a milled plastic lid to provide the conductivity and optical clarity necessary to electrically actuate the particles and observe them. The particles and medium were in the microfluidic chamber formed by using conductive glue to bond the plastic milled lid to the patterned silicon substrate. A correlation between the particle velocities and the electric field gradients was made using video microscopy and COMSOL Multiphysics ® simulations.