Abstract: The present invention is directed to provide a method for holding a silicon wafer, which can reduce contact scratches in contact with support members when holding a back surface of the silicon wafer, as well as prevent the wafer from bending when holding the back surface of the silicon wafer. The back surface of a silicon wafer of 300 millimeters or more in diameter and 700 micrometers to 1000 micrometers in thickness is held in contact with a support member or a suction member, specifically held within a region where a radius of the silicon wafer×0.50 to 0.80 from a center thereof. The silicon wafer is held in a state where the maximum amount of displacement within a wafer plane is 300 micrometers or less. The silicon wafer back surface is held in contact within the holding region in all the processes of holding the back surface of the silicon wafer in contact with the support member or the suction member.

Abstract: The invention provides a method of producing silicon single crystals which comprises using the CZ method under application of a magnetic field to the silicon melt and under application of an electric current containing a component perpendicular to this magnetic field, namely using the EMCZ method, adjusting the pulling rate in the process of single crystal growth and thereby growing a single crystal under conditions such that the outside diameter of the potential region of the ring-forming oxidation-induced stacking faults (R-OSF) occurring in the cross section of the crystal is within the range of 70% to 0% of the crystal diameter. By this, wafers for semiconductors excellent in device characteristics such as gate oxide integrity or the like can be produced with high productivity without formation of COPs with not less than 0.1 &mgr;m in size, or of dislocation clusters.

Abstract: A surface acoustic wave resonator having an interdigital transducer on a piezoelectric substrate. Grating reflectors, which have electrode strips of the same width and the same pitch as those of electrodes of the interdigital transducer and of a number smaller than 1/5 that of said electrodes of said interdigital transducer, are disposed at the intervals equal to said pitch at both sides of said interdigital transducer on a surface wave propagation path. The electrode portion of the interdigital transducer is weighted so that the aperture of the interdigital transducer is maximum at the center of the interdigital transducer and uniformly decreases toward its both sides along respective sides of a rhombus with its vertices at the centers of the outermost electrode strips of the grating reflectors.