Insights into Bulk Defects in n-type Monocrystalline Silicon Wafers via Temperature-Dependent Micro-Photoluminescence Spectroscopy
conference paper
In this study, we use temperature-dependent microphotoluminescence
spectroscopy to investigate non-uniform bulk
defects in n-type Czochralski and float-zone silicon wafers. For
both wafer types, we observe defect photoluminescence (PL) with
peak energy between 0.78 eV and 0.85 eV emerge as the
temperature is decreased from 300 K to 80 K, along with an
associated 10–100 times reduction in the band-to-band (BB) PL.
This similarity in the shape of the spectral PL between the two
wafer types suggests that the origin of the defects may be related.
For the float-zone wafers, the defect PL is present even in regions
appearing bright in conventional band-to-band PL imaging,
suggesting that the bulk defect exists across the entire wafer, but
is spatially inhomogeneous. Defect parameters are extracted by
fitting the ratio of the integrated defect to band-to-band PL ratio
using a modified Arrhenius equation derived from the Shockley-
Read-Hall defect theory. We determine similar defect parameters
for the FZ wafer within the bright and dark regions: a single defect
species located at 150 to 160 meV from the valence band-edge and
a capture cross-section temperature-dependence following an
inverse power law with exponent of approximately 2. For the Cz
wafer the defect is located 325 meV from the valence band-edge,
as expected from the peak PL position, and a capture cross-section
temperature exponent of approximately 2.5 was determined. This
suggests that a different recombination process is responsible for
the same defect PL band in each wafer type.
spectroscopy to investigate non-uniform bulk
defects in n-type Czochralski and float-zone silicon wafers. For
both wafer types, we observe defect photoluminescence (PL) with
peak energy between 0.78 eV and 0.85 eV emerge as the
temperature is decreased from 300 K to 80 K, along with an
associated 10–100 times reduction in the band-to-band (BB) PL.
This similarity in the shape of the spectral PL between the two
wafer types suggests that the origin of the defects may be related.
For the float-zone wafers, the defect PL is present even in regions
appearing bright in conventional band-to-band PL imaging,
suggesting that the bulk defect exists across the entire wafer, but
is spatially inhomogeneous. Defect parameters are extracted by
fitting the ratio of the integrated defect to band-to-band PL ratio
using a modified Arrhenius equation derived from the Shockley-
Read-Hall defect theory. We determine similar defect parameters
for the FZ wafer within the bright and dark regions: a single defect
species located at 150 to 160 meV from the valence band-edge and
a capture cross-section temperature-dependence following an
inverse power law with exponent of approximately 2. For the Cz
wafer the defect is located 325 meV from the valence band-edge,
as expected from the peak PL position, and a capture cross-section
temperature exponent of approximately 2.5 was determined. This
suggests that a different recombination process is responsible for
the same defect PL band in each wafer type.
Topics
TNO Identifier
875637
Source title
2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC)
Pages
1-4
Files
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