Carbon and oxygen role for thermally induced microdefect formation in silicon crystals

Thermally induced microdefect formation phenomena are investigated in connection with oxygen and carbon in silicon crystals by using x-ray diffraction, infrared absorption, and etching/optical microscope observation techniques. In order to investigate the carbon and oxygen role for microdefect formation, oxygen-diffused floating-zone-grown silicon crystals, containing various carbon contents, are thermally treated. As a result, it is ascertained that the coexistence of both carbon and oxygen is necessary for the microdefect formation. It is also determined that the critical oxygen concentration for microdefect introduction by the heat treatment is about (5–6) ×1017 cm−3.