Method for controlling the oxygen level of silicon rods pulled according to the Czochralski technique

摘要

A method for controlling the oxygen concentration profile of a rod of crystalline material such as silicon being pulled from a melt in a crucible includes varying the crucible rotation speed during the pulling process. In a preferred embodiment, the average oxygen concentration profile of a rod pulled at a constant crucible rotation speed is measured and then this information is used in growing another rod by controlling the crucible rotation speed during the pulling process so that its slope is opposite to the slope of the measured average oxygen concentration profile.