Hoseinpur Arman, Andersson Stefan, Tang Kai, Safarian Jafar
Department of Materials Technology, Norwegian University of Science and Technology (NTNU), Trondheim 7034, Norway.
SINTEF Industry, Trondheim 7465, Norway.
Langmuir. 2021 Jun 22;37(24):7473-7485. doi: 10.1021/acs.langmuir.1c00876. Epub 2021 Jun 7.
The evaporation of P from liquid Si under vacuum and reduced pressures of H, He, and Ar was studied to evaluate the feasibility of effective P removal with insignificant Si loss. It was found that the introduction of Ar and He inert gases at low pressures reduces the rate of P removal, and their pressure decrease will increase the process rate. Moreover, the kinetics of P removal was higher in He than in Ar, with simultaneous lower Si loss. Under reduced pressures of H gas, however, the P removal rate was higher than that under vacuum conditions with the lowest Si loss. Quantum chemistry and dynamics simulations were applied, and the results indicated that P can maintain its momentum for longer distances in H once it is evaporated from the melt surface and then can travel far away from the surface, while Si atoms lose their momentum in closer distances, yielding less net Si flux to the gas phase. Moreover, this distance is significantly increased with decreasing pressure for H, He, and Ar gases; however, it is the largest for H and the lowest for Ar for a given pressure, while the temperature effect is insignificant. The rate of P evaporation was accelerated by applying an additional vacuum tube close to the melt surface for taking out the hot gas particles before they lose their temperature and velocity. It was shown that this technique contributes to the rate of process by preventing condensing gas stream back to the melt surface.
研究了在真空以及氢气、氦气和氩气的减压条件下，磷从液态硅中的蒸发情况，以评估在硅损失极小的情况下有效去除磷的可行性。研究发现，在低压下引入氩气和氦气惰性气体会降低磷的去除速率，而降低它们的压力会提高该过程的速率。此外，在氦气中磷的去除动力学比在氩气中更高，同时硅的损失更低。然而，在氢气的减压条件下，磷的去除速率高于真空条件下的速率，且硅的损失最小。应用了量子化学和动力学模拟，结果表明，磷一旦从熔体表面蒸发，在氢气中能够在更长距离上保持其动量，然后可以远离表面，而硅原子在更近的距离就失去了动量，进入气相的净硅通量较少。此外，对于氢气、氦气和氩气，随着压力降低，这个距离会显著增加；然而，在给定压力下，氢气的这个距离最大，氩气的最小，而温度的影响不显著。通过在靠近熔体表面处设置一个额外的真空管，在热气颗粒失去温度和速度之前将其抽出，加速了磷的蒸发速率。结果表明，该技术通过防止冷凝气流回到熔体表面，提高了过程速率。
