Method of manufacturing a single crystal silicon rod

A method for manufacturing a single crystal silicon rod having a diameter of 80 mm or more comprising the steps of:

• pulling up a seed silicon crystal contacted by a silicon melt in an atmosphere of protective gas, lowering the temperature of said rod directly to about 900.degree. C., reducing the susceptibility of said silicon rod to formation of dislocation by subsequent thermal treatments by then reducing the intracrystal temperature of the growing single crystal silicon rod from 900.degree. C. to 500.degree. C. in less than 4 hours and maintaining the intracrystal temperature gradient of said single crystal silicon rod at a value less than 100.degree. C./cm.