Growth of Si single ingots with large diameter (∼45 cmφ) and high yield of high conversion efficiency (≥ 18 %) cells using a small crucible (∼50 cmφ) by noncontact crucible method

Abstract

As an advanced cast method, we proposed the noncontact crucible (NOC) method to obtain ingots with large diameter and diameter ratio using small crucible. By controlling the size of the low-temperature region, a Si single ingot with a 45 cm diameter was obtained using a 50 cm diameter crucible. As the oxygen concentration was always lower than that of Czochralski (CZ) ingots, a p-type ingot was prepared to determine the distribution of conversion efficiency. All (100 %) regular solar cells grown by the NOC method had higher conversion efficiency than 18.2% when using the same solar cell structure and process to obtain the conversion efficiency of 19.0% for a p-type CZ wafer. Therefore, the final yield of high efficiency solar cells prepared by the NOC method will be higher than that of the cast method when the suitable diameter will be selected.