Monolike ingot growth by directional solidification of Solar Grade silicon

Abstract

In the frame of permanent objective to increase solar cell efficiency and to decrease production cost the monolike ingot process was designed which combine multicrystalline (mc) productivity and monocrystalline structure performances. As a raw material the mc-Solar Grade silicon (SoG-Si) was used because it is less expensive than the Si purified by gas chemical route (Siemens process or equivalent), Usage of the mc-SoG-Si for growing silicon ingots by monolike process should contribute to the ingot and wafer manufacturing cost decrease. SoG silicon using would be developed all the more fast since it enables to produce high efficiency solar cells. It is why the monolike process have been tested and optimized for Kazakhstan mc-SoG silicon. The objective of this work was study of the higher level content impurities influences on the crystal defect generation (mainly dislocations) of the monocrystalline structure. Visual monocrystalline structure, minority carrier lifetime mapping, and photoluminescence techniques were used to study the monolike ingots obtained from Kazakhstan’s mc-SoG silicon.

The Possibility of Silicon Purification by Metallurgical Methods: Part I

“…Namely, the slag refining method was used for purification. The Institute of Physics and Technology (Almaty, Kazakhstan) has conducted several studies on methods of metallurgical-grade silicon (MG-Si) production and purification of silicon to UMG-Si, as well as research on silane production methods [16][17][18][19][20][21][22]. As a result of previously conducted studies and works, purified silicon samples and Si crystals grown by the Czochralski method were obtained on a laboratory scale, approximately 2-3 kg.…”

“…Based on the results of the literature sources [23][24][25], as well as a number of our preliminary research concerning this topic [16][17][18][19][20][21][22], further development and improvement of technologies for obtaining and refining Si to solar quality is promising and of strategic importance for the Si industry of Kazakhstan.…”