Formation of Si₂N₂O Microcrystalline Precipitates near the Quartz Crucible Wall Coated with Silicon Nitride in Cast-Grown Silicon

Abstract

The chemical reaction near the crucible wall during directional solidification of Si crystals for solar cells has been investigated. Fragments of the crucible that were used for the crystal growth of a Si ingot were examined. As results, we found that a chemical reaction took place at the coating/crucible interface and that silicon oxynitride particles precipitated near the crucible wall. The oxynitride precipitates were determined as stoichiometric Si2N2O and were revealed not to be amorphous but of orthorhombic crystal symmetry. We show crucial evidence of the formation of stoichiometric Si2N2O microcrystalline precipitates inside the Si crystal.

Distribution of light-element impurities in Si crystals grown by seed-casting method

“…Control of these light-element impurities, i.e., interstitial oxygen (O i ) and substitutional carbon (C s ), has become essential because light-element impurities affect solar sell performance through defect formation. [17][18][19][20][21][22][23][24][25][26][27] It is necessary to accurately clarify the mechanism of generation of the light-element impurities in Si crystals grown by the seed-casting method to develop methods to suppress the degradation in solar cell efficiency.…”

Thermodynamics of amorphous SiN(O)H dielectric films synthesized by plasma‐enhanced chemical vapor deposition

“…Consideration of the thermodynamics of amorphous phases in the Si–O–N system is also important when considering the solubility, nucleation, and growth of various precipitates in high‐temperature processes involving the growth and refinement of crystalline phases such as Si, SiO 2 , Si 3 N 4 , and Si 2 N 2 O . Examination of the thermochemistry of a‐SiNH and a‐SiNOH materials will also broaden the understanding of the energy landscape in the Si–O–N and Si–O–N–H systems by examining previously unexplored portions of these phase diagrams.…”

Oxygen precipitates distributed around random grain boundaries in a cast-grown multicrystalline silicon crystal

“…[1][2][3][4][5] Recently, it has been revealed that oxygen precipitates are often formed in the crystal during crystal growth and reduce the carrier lifetime. [6][7][8][9][10] Furthermore, GBs and dislocations also act as carrier recombination centers of minority carriers and affect the cell performance. 11,12) There have been many studies investigating oxygen and oxygen precipitates in sc-Si being used for large-scale integration (LSI) devices.…”