Thermal stability of silicon surface passivation by APCVD Al 2O3
- verfasst von
- Lachlan E. Black, Thomas Allen, Andres Cuevas, Keith R. McIntosh, Boris Veith, Jan Schmidt
- Abstract
We investigate the thermal stability of silicon surface passivation provided by aluminium oxide (Al2O3) films deposited using atmospheric pressure chemical vapour deposition (APCVD) and fired in a belt furnace at a peak temperature of ~810 C. Firing stability is investigated for p- and n-type substrates as a function of Al2O3 film thickness both with and without a plasma-enhanced chemical vapour deposition (PECVD) SiNx capping layer, and for boron-diffused surfaces with a ~10 nm Al2O3 film only. Excellent thermal stability of the passivation is demonstrated, with effective carrier lifetimes in n-type silicon wafers remaining stable or even improving after firing, and lifetimes in p-type wafers initially degrading slightly but recovering to above their initial values following ~10 min illumination by a halogen lamp at ~20 mW/cm 2. Film thickness appears to be unimportant to stability, as does the presence of the capping layer. Surface recombination velocities of less than 3 cm/s for 1.35 Ω cm p-type and less than 2 cm/s for 1.2 Ω cm n-type substrates are measured after firing and illumination. The passivation of boron-diffused surfaces is also shown to improve slightly following firing, with a post-firing saturation current density of 42 fA/cm2 on a diffusion with a sheet resistance of 100 Ω/□ and surface dopant concentration of ~1.3×1019 cm-3. Capacitance-voltage (C-V) measurements show that short firing times result in an initial reduction of the interface defect density Dit and a slight increase of the negative insulator fixed charge density Qf, while longer firing results in a substantial increase in both Qf and Dit.
- Externe Organisation(en)
-
Australian National University
PV Lighthouse
Institut für Solarenergieforschung GmbH (ISFH)
- Typ
- Artikel
- Journal
- Solar Energy Materials and Solar Cells
- Band
- 120
- Seiten
- 339-345
- Anzahl der Seiten
- 7
- ISSN
- 0927-0248
- Publikationsdatum
- 2014
- Publikationsstatus
- Veröffentlicht
- Peer-reviewed
- Ja
- ASJC Scopus Sachgebiete
- Elektronische, optische und magnetische Materialien, Erneuerbare Energien, Nachhaltigkeit und Umwelt, Oberflächen, Beschichtungen und Folien
- Ziele für nachhaltige Entwicklung
- SDG 7 – Erschwingliche und saubere Energie
- Elektronische Version(en)
-
https://doi.org/10.1016/j.solmat.2013.05.048 (Zugang:
Geschlossen)
https://hdl.handle.net/1885/29928 (Zugang: Offen)
