The Study On The Analytical Method Of Trace Metal Element Content In High Purity Polysilicon

Solar energy is an important,new,and useful renewable clean energy,its reserves are huge,there is no environmental pollution,has a seductive vision.As the downstream customers solar cell manufacturers on the conversion rate of the battery chip is getting higher and higher,so the quality of silicon material also put forward higher requirements.Previously limited to the phosphorus test,boron detection resistivity determination,the current requirements for each batch of silicon material should have accurate donor concentration,the concentration of the main concentration and metal impurities reported results.So need to establish a complete set of silicon material in the impurity concentration analysis test method.In this paper,the high purity polycrystalline silicon produced by a company was used as the sample,and the trace elements such as B,P,Cr,Fe,Ni,Cu and Zn were analyzed.The results show that the pretreatment of the sample and the detection limit of the inductively coupled plasma mass spectrometry(ICP-MS)instrument and the effectiveness of the analytical method are as follows:(1)For the polysilicon material is difficult to dissolve,after dissolved the substrate is high,using closed digestion and exposure digestion contrast,By comparing the digestion time of the sample,the amount of digestion reagent,the recovery rate and the blank value,it was concluded that the sealing digestion time was short and the sample treatment process introduced less impurities.(2)About the B element at 50 above the volatile problem,? Using the method of adding complexing agent,the effective inhibition of the volatilization effect of B.For the P element determination is susceptible to other compounds or elements interfere with the problem,select PO as P to be measured elements,and the instrument parameters are adjusted and adjusted reasonably,which effectively reduces the background value of P-element detection by inductively coupled plasma mass spectrometry(ICP-MS).(3)For the simultaneous determination of the transition metal elements Cr,Fe,Ni,Cu,Zn,which affect the performance of the silicon devices downstream of polysilicon Perform isotope interference analyze,Multi-atom ion interference analyze,Analysis of equipment stability analyze.At last the isotopes of elements are optimized and sorted,and the parameters of the elements are optimized and tuned according to the characteristics of different elements.The equipment parameters to optimize the tuning,and ultimately to the instrument sensitivity,detection limit,the recovery rate of each element to meet the high purity polysilicon trace metal impurity element determination requirements.