Abstract: This invention is directed to a method for the production of a dislocation-free silicon single crystal by the Czochralski method. This method attains growth of the main body part of the dislocation-free silicon single crystal by immersing a seed crystal in a melt of silicon and then pulling the seed crystal without recourse to the necking. The seed crystal thus used is a dislocation-free silicon single crystal. The horizontal maximum length of the part of the seed crystal being immersed in the melt at the time of completing the immersion of the seed crystal in the melt is not less than 5 mm. The immersing rate of the seed crystal in the melt is not more than 2.8 mm/min and the part of the seed crystal to be immersed in the melt is a crystal as grown.

Abstract: A cleaning solution for achieving highly accurate cleaning of silicon semiconductors and silicon oxides. The solution which enables a great reduction in the metal contaminants and the number of fine particles adhered on the surfaces and retention of the hydrophilic property of the surfaces to prevent the surfaces from being unstable, comprising an aqueous acidic solution containing 0.005% by weight or more to less than 0.05% by weight hydrogen fluoride and 0.3% by weight or more to 20.0% by weight or less hydrogen peroxide and having a pH in the range from 1 or more to less than 5.

Abstract: A single silicon crystal wafer produced by the Czochvalski method and measuring not less than 100 mm in diameter, a single silicon crystal having low OSF density induced by oxidation, wherein regarding the local resistivity measured by the spread resistance method on the surface of said wafer subjected in advance to a heat treatment for extinction of oxygen donor, the proportion of the number of points of measurement registering errors exceeding .+-.1.0% of the mean value is not more than 35% of the total number of points of measurement, and regarding the distribution of oxygen concentration in solid solution in the wafer surface, the difference between the maximum and the minimum is not more than 2.0% of the maximum, and a method for production thereof.