Effects of annealing in oxygen and nitrogen atmosphere on F.Z. silicon wafers

F.Z. silicon wafers were submitted to high temperature annealings during long times in oxygen and in nitrogen atmosphere in order to reproduce the same treatments which are necessary to develop power and high voltage transistors or diodes. It is shown by electrical techniques (microwave detected photoconductivity decay and surface photovoltage) and by revelation techniques (scanning infrared microscope, X-ray topography, Fourier transformed infrared spectroscopy, chemical etchings) that annealings in nitrogen added to annealings in oxygen have a deleterious effect on the lifetime of minority carriers and can create dislocations and precipitates.