RECENT PROGRESS IN OCTAGON GROWTH USING EDGE-DEFINED FILM-FED GROWTH

The growth of silicon tubes having an octagon shape with a face width over 10 cm has been reported previously. These octagon tubes are now being grown routinely on a pilot production line to lengths over 4.5 m and at areal growth rates of about 150 cm2 of silicon sheet per minute per furnace. Continuous replenishment of the melt during crystal growth, developed for the growth of smaller nonagon tubes, has been enhanced and deployed in the octagon furnaces, resulting in improved growth length between freezes and improved electronic properties. Octagon tubes are cut by laser into 10 cm × 10 cm blanks, which are then fabricated into solar cells with efficiencies over 13%. © 1990.