The effect of high pressure - high temperature treatment on neutron irradiation induced defects in Czochralski silicon

摘要

Czochralski-grown (Cz-grown) silicon crystals of the same initial oxygen content (8.33 * 10~(17) cm~(-3)) were subjected to various high temperature - high pressure (HTHP) treatments for different time durations. Subsequently, the crystals were irradiated by fast neutrons at ～50 °C. One of the main defects form is VO pair (A-Center) usually identified in the Infrared (IR) Spectra by the 830cm~(-1) Localized Vibrational Mode (LVM) band. Upon annealing, this defect is converted to the VO_2 defect responsible for a LVM band at 887cm~(-1). The purpose of this work is to study the effect of various combinations of HTHP treatment prior to irradiation on the annealing behaviour of the VO defect and particularly on its conversion to the VO_2 defect. We have concluded that the conversion of VO to VO_2 depends on the forms of oxygen impurity (i.e. oxygen aggregates, precipitates etc.) and on other defects created in the sample after the HTHP treatment, as for example dislocations and stacking faults.