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Full-Text Articles in Engineering Science and Materials
Microporous Silicon Dioxide/Vycor Membranes For Gas Separation, Justin R. Barone
Microporous Silicon Dioxide/Vycor Membranes For Gas Separation, Justin R. Barone
Theses
This study focused on producing membranes for molecular sieving of gases by reducing the pore size of an already existing membrane structure. To do this, SiO2 was deposited inside the pores of a Vycor tube with initial pore diameter of 4 nm. The film deposition took place by a low pressure chemical vapor deposition (LPCVD) process where diethylsilane (DES) and nitrous oxide (N2O) were used as precursor gases. A counterflow reactant geometry was used where the precursor gases were flowed on both sides of the porous membrane. This deposition geometry gave higher selectivities and better mechanical stability. …
Synthesis And Characterization Of Silicon Dioxide Thin Films By Low Pressure Chemical Vapor Deposition Using Ditertiarybutylsilane And Oxygen, Sung-Jun Lee
Theses
This study is focused on the synthesis and characterization of silicon dioxide thin films deposited on silicon wafers by Low Pressure Chemical Vapor Deposition (LPCVD), using ditertiarybutylsilane (DTBS) as a precursor and oxygen as the oxidant. The dependence of film growth rate on various process parameters were studied. The growth rate was found to follow an Arrhenius curve with the variation in the temperature with an activation energy of 12.6 kcal/mol. The growth rate was found to be inversely proportional to the temperature in the range 550-750 °C. The refractive index and density were observed to be close to 1.47 …
Low Pressure Chemical Vapor Deposition Of Silicon Dioxide And Phosphosilicate Glass Thin Films, Vijayalakshmi Venkatesan
Low Pressure Chemical Vapor Deposition Of Silicon Dioxide And Phosphosilicate Glass Thin Films, Vijayalakshmi Venkatesan
Theses
Silicon dioxide thin films were synthesized on silicon and quartz wafers using Ditertiarybutylsilane(DTBS) and oxygen as precursors. Trimethylphosphite (TMP) was injected to obtain phosphosilicate glass. The films were processed at different temperatures between 700°C and 850°C at a constant pressure, and at different flow ratios of the precursors. The films deposited were uniform, amorphous and the composition of the films varied with deposition temperature and precursor flow ratios. The deposition rate increased with increasing temperature and with increasing TMP flow rate. The stresses were very low tensile in the case of undoped silicon dioxide film and tended towards being less …
Synthesis Of Silicon Oxide/Vycor Composite Membrane Structures By An Optimized Lpcvd Process, Abhijit Datta
Synthesis Of Silicon Oxide/Vycor Composite Membrane Structures By An Optimized Lpcvd Process, Abhijit Datta
Theses
This study is focused on development of highly selective ceramic membrane structures consisting of silicon dioxide films synthesized by low pressure chemical vapor deposition (LPCVD) on mesoporous Vycor substrates. The ability of easily altering the composition of such films by varying the LPCVD processing parameters affords the opportunity of microengineering the pore structure by reducing the diameters of pre-existing pores in the support. The process parameters investigated include, deposition temperature, total pressure, and flow rate of oxygen. Both the kinetics and select properties of the deposits were examined. The growth rate as a function of temperature was seen to follow …