Competitive gettering of iron in silicon photovoltaics: Oxide precipitates versus phosphorus diffusion

Abstract

Experiments have been conducted to understand the behaviour of iron in silicon containing oxide precipitates and associated defects (dislocations and stacking faults), which is subjected to phosphorus diffusion gettering. Injection-dependent minority carrier lifetime measurements are analysed to provide quantitative information on the degree to which the precipitates and associated defects are decorated with iron impurities. These data are correlated with bulk iron measurements based on the photodissociation of FeB pairs. Iron in the vicinity of oxide precipitates in samples with relatively low levels of bulk iron contamination (< 5 × 1012 cm−3) can be gettered to some extent. Higher levels of bulk iron contamination (> 1.2 × 1013 cm−3) result in irreversible behaviour, suggesting iron precipitation in the vicinity of oxide precipitates. Bulk iron is preferentially gettered to the phosphorus diffused layer opposed to the oxide precipitates and associated defects.

Re-evaluation of the SRH-parameters for the FeGa defect

“…An important uncertainty to the actual iron content is given by the drive-in diffusion after implantation. A loss of iron could occur via segregation in the growing oxide (gettering) or in the etched surface region [11]. Also precipitation of iron could occur [11], resulting in iron that is not detectable via lifetime evaluations, since precipitated iron does not take part in the metastable defect state change [12].…”

“…A loss of iron could occur via segregation in the growing oxide (gettering) or in the etched surface region [11]. Also precipitation of iron could occur [11], resulting in iron that is not detectable via lifetime evaluations, since precipitated iron does not take part in the metastable defect state change [12]. Another reason for a lower iron content is gettering in the surface passivation layer [13].…”

Investigating Wafer Quality in Industrial Czochralski‐Grown Gallium‐Doped p‐Type Silicon Ingots with Melt Recharging

“…It is known that OPs can act as internal gettering sites for metallic impurities, effectively increasing the precipitation of transition metal impurities (such as Fe). [21,22] Such impurity-decorated OPs and transition metal impurities (both in the dissolved and precipitated states) also act as effective recombination centers in p-type silicon. [23,24] 2.2.…”

Glass alteration in the process of long-term corrosion caused by internal stress: A comparative study of degraded and intact domains in 19th century semi-opaque turquoise glass seed beads using micro-FTIR spectroscopy and SEM

“…The strain-enhanced diffusion phenomenon is analogous to the diffusion of metals atoms that occurs during the internal gettering process often employed for the integrated circuit manufacturing[53,54,55] …”