[20p-S611-1~17] 16.3 Bulk, thin-film and other silicon-based solar cells

[20p-S611-1] Growth of Si ingots with 45 cm diameter using a crucible with 50 cm diameter by a Noncontact Crucible (NOC) furnace with 2 zone heaters

〇Kazuo Nakajima¹, Satoshi Ono¹, Yuzuru Kaneko¹, Ryota Murai¹, Katuhiko Shirasawa², Tetuo Fukuda², Hidetaka Takato² (1.JST FUTURE-PV, 2.FREA)

Keywords:solar cells,large diameter,large diameter ratio

We have studied the growth of a large ingot without contact to the crucible wall even using a small crucible by our original Noncontact Crucible (NOC) method. To design a more-simple furnace for practice use, we have developed the NOC furnace with two zone-heaters. The furnace was able to create a low-temperature region in the Si melt with a diameter as large as 0.9 of the crucible diameter. Using the furnace, a single bulk crystal with the diameter ratio more than 0.9 and the diameter of more than 45.0 cm were obtained using crucibles of 50 cm diameter. The highest conversion efficiency of 18.8% and the lowest conversion efficiency of 18.2% were obtained for our wafers using the same solar cell structure and process to obtain the conversion efficiency of 19.0% for a Czochralski (CZ) wafer in AIST, Fukushima.