Patent ID: 7663383
Filing Date: 2010-02-16
Classification: G01N,H01L

Abstract:
1. A method for detection and analysis of an impurity content of refined metallurgical silicon, comprising: (1) selecting a plurality of measuring points along a crystallization direction on a specimen of metallurgical silicon selected from a crystal rod and a crystal ingot, with a distance between two adjacent measuring points selected to be no more than 2 cm on the crystal rod, and no more than 1 cm on the crystal ingot, where a ratio of a weight from a starting point to each measuring point of the crystal rod or the crystal ingot and a material weight of the crystal rod or the crystal ingot is called a “crystallized fraction”, and measuring a resistivity at each measuring point and acquiring a measured value of resistivity according to a distribution of crystallized fraction; (2) determining an estimated value of a content of boron and a content of phosphorus at each measuring point based on an estimated value of impurity content as well as a segregate coefficient of original silicon material, and calculating an estimated net redundant carrier concentration and then calculating a measured value of net redundant carrier concentration according to a measured value of resistivity at every measuring point; (3) comparing the estimated value of net redundant carrier concentration with the measured value, and adjusting the estimated value according to an exponential segregation of each point as well as the crystallized fraction to get a new estimated net redundant carrier concentration, and repeating the above steps and use regression analysis to determine the impurity content distribution of boron and phosphorus, so that an average square of a difference of the estimated value and the measured value of the net redundant carrier concentration is less than 0.01; and (4) determining an average impurity content of boron and phosphorus in the silicon material according to a distribution status of impurity based on all the measuring points.