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多晶硅中的杂质通常用光谱分析法来测定,但测磷的灵敏度不够高。近来人们用间接法,先使磷酸根与钼酸铵生成磷钼杂多酸,再用乙酸正丁酯萃取此杂多酸,使其与砷、硅等分离,然后用光谱法测定钼以间接测定磷,这样提高了测定灵敏度。我们考虑到钼在苦杏仁酸存在下的极谱催化波十分灵敏,因此将有机相中的磷钼杂多酸反萃于氨溶液中,加入硫酸、苦杏仁酸和氯酸钠,极谱测钼的催化波,从而间接测定磷。实验结果表明催化波法可测至0.005微克磷/11毫升,能满足一般多晶硅分析的要求。
Impurities in polycrystalline silicon are usually measured spectrometrically, but the sensitivity of phosphorus is not high enough. Recently, people use indirect method, the first phosphate and ammonium molybdate molybdophosphate heteropoly acid, and then n-butyl acetate extraction of this heteropoly acid, with arsenic, silicon and other separation, and then determined by spectrophotometry molybdenum indirect Determination of phosphorus, thus increasing the measurement sensitivity. We consider molybdenum in the presence of mandelic acid polarographic catalytic wave is very sensitive, so the organic phase of phosphomolybdic heteropoly acid back to ammonia solution, adding sulfuric acid, mandelic acid and sodium chlorate, polarographic Molybdenum catalytic wave, which indirectly measured phosphorus. Experimental results show that the catalytic wave method can be measured to 0.005 micrograms of phosphorus / 11 ml, to meet the general requirements of polysilicon analysis.