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Numerical modeling of carbon distribution and precipitation during directional solidification of photovoltaic silicon
摘要： Numerical modeling is used to investigate carbon distribution and precipitation in directional solidification of multicrystalline silicon. Computations are performed for samples of 6 cm in diameter grown in a Vertical Bridgman Freezing (VGF) system starting from silicon feedstock with different grades of contamination in carbon. The value of the unknown reaction rate coefficient governing the carbon precipitation in the silicon melt was estimated in the present work by comparing the numerically computed concentration profiles to the experimental results taken from the literature. Numerical results show that the growth rate has a significant influence on the interface deflection, melt convection and carbon precipitation. It is found that the silicon samples grown from the melts of low carbon contamination (< 1018 at/cm3) exhibit low content in SiC precipitates, even if they are solidified at high growth rates (1–2 cm/h). The samples with high initial carbon contamination (5 × 1018 at/cm3) should be solidified at much lower rates (0.2 cm/h) in order to avoid the formation of SiC precipitates.
关键词： Carbon transport and precipitation,Directional solidification,Impurities,Semiconducting silicon,Computer simulation
更新于2025-09-16 10:30:52
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The influence of travelling magnetic field on phosphorus distribution in n-type multi-crystalline silicon
摘要： The influence of different melt streams on the distribution of phosphorus in multi-crystalline silicon ingot was studied. Phosphorus-doped multi-crystalline silicon (mc-Si) ingots were directionally solidified using travelling magnetic fields (TMF) to alter axial phosphorus profiles. Resistivity distributions in the crystallized n-type ingots were measured along the ingot length. Different Lorentz forces were applied in order to enhance melt stirring and with that to transport phosphorus more rapid towards the melt surface. A new rectangular setup was developed, which enables simultaneous directional solidification of 4 G0-sized mc-Si ingots (80 x 80 x 60 mm3) under the influence of TMF. 900 g ingots with different initial level of phosphorus doping were grown, and dopant concentrations in ingots were related to stirring intensities. The phosphorus evaporation rate significantly affects axial dopant profile of mc-Si material, thus this approach can be used as a powerful tool to control and tailor resistivity distribution along phosphorus-doped mc-Si ingots.
关键词： A1 Directional solidification,A1 Magnetic fields,B1 Semiconducting silicon,B3 Solar cells,A1 Doping
更新于2025-09-10 09:29:36
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The influence of growth temperature on 4H-SiC epilayers grown on different off-angle (0 0 0 1) Si-face substrates
摘要： In this paper, homoepitaxial growth was performed on on-axis, 4° and 8° o?-axis 4H-SiC (0001) Si-face substrate by using our home-made vertical hot wall LPCVD reactor and SiH4 + C2H4 + H2 + HCl gas system. The in?uence mechanism of growth temperature on the crystal quality, the growth rate and surface morphology is studied. The growth rate increased with the increase of growth temperature, and the epitaxial wafer surface morphology is more excellent by the increasing of o?-angle. The results demonstrate that growth temperature is a fundamental process parameter to optimize.
关键词： A3. Chemical vapor deposition processes,A2. Growth from vapor,A1. Characterization,B2. Semiconducting silicon compounds
更新于2025-09-04 15:30:14