Surface and bulk passivation of multicrystalline silicon solar cells by ...

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Figure 2.7 The calculated reflectance and absorbance spectra of a Si solar cell operating
in air (thick lines) and in an encapsulated module (thin lines). The
nonabsorbing nitride is assumed to have n=2 for air and n=2.2 for module
operation [42].
2.3 SiΝ -Si Interface Structure
The microscopic origin of interfacial defects in SiΝ -Si structures has been investigated
by many researchers. Stemans reported the •Si =Si3 defect in Si/Si 3N4 interface, i.e., the
surface Si dangling bond [53], which was also described by Garcia et al. as the unpaired
hybrid pointing out of the Si surface [54].
It is reported that, during the SiN X deposition, the SiO X film is converted into an
oxynitride film [52, 55]. Hence, it can be expected that the actual interfacial region on a
silicon wafer covered by a PECVD SiN X film possesses some similarity to the one found
at the thermally grown Si-Si0 2 interface. Due to the presence of nitrogen and oxygen