Determination of phosphorus in semiconductor grade silicon by neutron activation analysis

A method of determination of phosphorus in silicon has been elaborated. The separation of phosphorus is based on the extraction of phosphomolybdic complex in the presence of hold-back carriers of Ta and Au. Contamination factors for various impurities were determined. The lower limit of determination equals 3.10-11 g P. Types of errors in the determination of concentration profiles are discussed. The method meets the following requirements: 1./ It ensures good separation of phosphorus from elements occuring in silicon plates (i.e. Ta, Au, Sn, Ge, Ce, Sb, As, Cu, and Na). 2./ It ensures high chemical yield of phosphorus separation. 3./ It ensures high efficiency of the measurement of 32P β-activity. 4./ It is simple and rapid, since, for the determination of a implantation profile, it is necessary to analyse several tens of layers. (T.G.)