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Transition Metals in a Cast‐Monocrystalline Silicon Ingot Studied by Silicon Nitride Gettering
Author(s) -
Sun Chang,
Liu AnYao,
Samadi Aref,
Chan Catherine,
Ciesla Alison,
Macdonald Daniel
Publication year - 2019
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201900456
Subject(s) - ingot , monocrystalline silicon , materials science , silicon , getter , metallurgy , wafer , impurity , silicon nitride , nitride , composite material , nanotechnology , alloy , chemistry , optoelectronics , organic chemistry , layer (electronics)
The concentrations of Cr, Fe, Ni, and Cu in a cast‐monocrystalline silicon ingot grown for solar cell applications are reported. Wafers taken from along the ingot are coated with silicon nitride films and annealed, causing mobile impurities to be gettered to the films. Secondary ion mass spectrometry is applied to measure the metal content in the silicon nitride films. The bulk concentrations of the gettered metals in samples along the ingot are found to be: Cr (3.3 × 10 10 –3.3 × 10 11 cm −3 ), Fe (3.2 × 10 11 –2.5 × 10 12 cm −3 ), Ni (1.5 × 10 12 –1.3 × 10 13 cm −3 ), and Cu (7.1 × 10 11 –3.2 × 10 13 cm −3 ). For each metal, the lower limit is measured on the wafer from the middle of the ingot, and the higher limit is measured on wafers from the bottom or the top. The results are compared with similar data recently measured on a high‐performance multicrystalline silicon ingot. The results provide insights into the total bulk concentrations of the metals in cast‐grown ingots.