INFLUENCE OF THERMAL HISTORY DURING CZOCHRALSKI SILICON CRYSTAL-GROWTH ON OISF NUCLEI FORMATION

The aim of this work was to study the impact of the crystal cooling ra te in the puller on oxidation-induced stacking fault (OISF) nuclei for mation. By modifying the thermal history of the crystal, by adding an in situ annealing step immediately after the completion of growth, it was possible to separate the effects of the thermal history from those due to other growth parameters, which are otherwise interconnected. T his allowed the critical temperature range for the control of stacking fault nuclei formation during crystal cooling to be identified: nucle ation proceeds most effectively between 1070 and 880 degrees C; in thi s temperature range, a long residence time of the crystal can induce a high density of OISF nuclei. In addition to this, a relationship betw een the OISF nuclei density and the degradation of the minority carrie r lifetime, prior to oxidation, is clearly observed, suggesting that O ISF nuclei, or other related defects, are active as recombination cent res for minority carriers in p-type silicon.