6. Growth of Crystalline Silicon for Solar Cells: Czochralski Si

Czochralski (CZ) silicon is widely used in the fabrication of high-efficiency solar cells in photovoltaic industry. It requires strict control of defects and impurities, which are harmful for the performances of solar cells. Therefore, the CZ silicon crystal growth aims at achieving defect-free single crystals for advanced solar cell wafers. Meanwhile, attention must be paid to the low cost of CZ silicon crystal growth. Therefore, it is necessary to develop novel crystal growth techniques suitable for practical application of photovoltaics. This chapter will review the fundamentals of CZ silicon and recent developments. The oxygen-related defects and control technologies are emphasized. Meanwhile, the novel crystal growth methods are introduced. The Ge doping in CZ silicon can not only improve the material’s mechanical strength, but also suppress the generation of boron–oxygen complexes. This will enable thinner solar cells at reduced cost and benefit the fabrication of high efficiency solar cells with low light-induced degradation effects.