PECVD-AlOx/SiNx passivation stacks on silicon: Effective charge dynamics and interface defect state spectroscopy

Jan Amaru Tofflinger, Abdelazize Laades, Caspar Leendertz, Liz Margarita Montanez, Lars Korte, Uta Sturzebecher, Hans Peter Sperlich, Bernd Rech

Producción científica: Contribución a una revistaArtículo de la conferenciarevisión exhaustiva

33 Citas (Scopus)

Resumen

The charge dynamics and the interface defect state density of AlOx/SiNx passivation stacks deposited by plasma-enhanced chemical vapor deposition (PECVD) on crystalline silicon (c-Si) wafers are investigated. High frequency (1 MHz) capacitance voltage (C-V) measurements were performed on stacks in the as deposited state and after an annealing step. C-V sweeps reveal an initially high negative charge density for the as deposited sample, activated by the thermal budget during SiNx deposition. However, this charge state is unstable and reduced owning to electron detrapping and emission into the c-Si upon applying moderate voltages. In the annealed sample, the AlOx/SiNx stack has a stable negative fixed charge. Both for as deposited and for annealed samples, applying a positive or negative constant gate voltage stress (Vstress) enhances or reduces the negative effective charge density (Qox,eff), respectively. Injection of charges from the c-Si into traps in the AlOx/SiNx stack is identified as the mechanism responsible for this behavior. We conclude that in addition to fixed negative charges trapping of negative charges near the interface is a crucial mechanism contributing to the total effective negative charge of the stack. Their contribution depends on the temperature and duration of the thermal treatment. Additionally, a large Vstress leads to generation of additional Si dangling bond defects over the entire c-Si bang gap at the c-Si/AlOx interface.

Idioma originalInglés
Páginas (desde-hasta)845-854
Número de páginas10
PublicaciónEnergy Procedia
Volumen55
DOI
EstadoPublicada - 2014
Publicado de forma externa
Evento4th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2014 - Hertogenbosch, Países Bajos
Duración: 25 mar. 201427 mar. 2014

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