Characterization of high-quality kerfless epitaxial silicon for solar cells: Defect sources and impact on minority-carrier lifetime

Journal Article · Tue Nov 14 00:00:00 EST 2017 · Journal of Crystal Growth

DOI:https://doi.org/10.1016/j.jcrysgro.2017.11.016· OSTI ID:1436471

Kivambe, Maulid M. ^[1]; Powell, Douglas M. ^[1]; Castellanos, Sergio ^[1]; Jensen, Mallory Ann ^[1]; Morishige, Ashley E. ^[1]; Lai, Barry ^[2]; Hao, Ruiying ^[3]; Ravi, T. S. ^[3]; Buonassisi, Tonio ^[1]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2. Argonne National Lab. (ANL), Argonne, IL (United States)
3. Crystal Solar Inc., Santa Clara, CA (United States)

We investigate the types and origins of structural defects in thin (<100 μm) kerfless epitaxial single crystal silicon grown on top of reorganized porous silicon layers. Although the structural defect density is low (has average defect density < 10⁴ cm^-2), localized areas with a defect density > 10⁵ cm^-2 are observed. Cross-sectional and systematic plan-view defect etching and microscopy reveals that the majority of stacking faults and dislocations originate at the interface between the porous silicon layer and the epitaxial wafer. Localised dislocation clusters are observed in regions of collapsed/deformed porous silicon and at decorated stacking faults. In localized regions of high extended defect density, increased minority-carrier recombination activity is observed. Evidence for impurity segregation to the extended defects (internal gettering), which is known to exacerbate carrier recombination is demonstrated. In conclusion, the impact of the defects on material performance and substrate re-use is also discussed.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Defense Programs (DP); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC02-06CH11357; EE0005314
• OSTI ID: 1436471
• Alternate ID(s): OSTI ID: 1576613
• Journal Information: Journal of Crystal Growth, Journal Name: Journal of Crystal Growth Journal Issue: C Vol. 483; ISSN 0022-0248
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
Chemical vapor deposition processes
Epitaxial silicon
Impurities
Line defects
Photovoltaics
Semiconducting silicon