FULL-SCALE EXPERIMENTS ON SOLID-PELLETS FEED CONTINUOUS CZOCHRALSKI GROWTH OF SILICON-CRYSTALS

Two long-term solid-pellets feed continuous Czochralski growth experim ents were performed in an industrial Czochralski crystal puller as an extension to our previous work [7]. The goals of these experiments wer e to examine how polysilicon pellets would melt in a standard Cz syste m, to discover the thermal effects the pellets would have on the overa ll melt, and to find if pellet addition could be an effective melt rep lenishment technique. These experiments demonstrate that the quality o f the melt for the CCz growth is based heavily on the surface temperat ure of the melt. A novel characterization method (''impact severity'') is developed to characterize the quality of the CCz melt. Stable feed rate and melt conditions were achieved for three different pull rates . These experiments demonstrate that the process is technically feasib le, and can be retrofitted to the existing industrial systems. Several critical issues that need to be addressed to develop a successful CCz process are also discussed.