Relating Microdefects to Growth Conditions in Czochralski Si Crystal Growth

Abstract

The formation of grown-in defects in silicon crystals is controlled by the concentration of intrinsic point defects. Under steady-state conditions, the type of the prevailing point defect species is linked to the ratio of pull rate (v) and temperature gradient (G) in the crystal at the solidification front. It has been shown that this ratio as well as computed point defect distributions are in good agreement with experimental data. In this paper, we couple transient heat transfer with transient point defect models and show that the quasi-steady assumption and the v/G criteria are no longer valid if strong variations in the pulling velocity occur. Therefore, for a detailed understanding how defects are related to growth conditions, the thermal history should not be neglected.