AXIAL MICROSCOPIC DISTRIBUTION OF GROWN-IN DEFECTS IN CZOCHRALSKI-GROWN SILICON-CRYSTALS

The axial microscopic distribution of grown-in defects in Czochralski silicon was studied by means of IR light scattering tomography (LST) a nd preferential etching. IR scattering defects (defects observed with LST) were found to degrade the gate oxide integrity yield, and the axi al density distribution of IR scattering defects and flow patterns (we dge-shaped etch patterns) fluctuated with oxygen concentration fluctua tions along the growth axis. However, the defect density did not depen d directly on oxygen concentration. It is considered that the formatio n of IR scattering defects is related to the solid-liquid intertace te mperature fluctuations.