SEM investigation of structural defect hydrogen passivation in silicon

The results of the investigation of the structural defect passivation in solar cells made from both shaped polycrystalline and monocrystalline CZ-silicon by means of scanning electron microscope (SEM) in the electron beam induced current mode (EBIC) are reported. Atomic hydrogen effectively passivates the different types of grain boundaries in the shaped polysilicon as well as the microdefects in the CZ-silicon. The changes of the hydrogenated sample electrophysical properties are observed during the electron beam irradiation in SEM (experiments “in situ”). These changes indicate a hydrogen state variation in silicon crystal. The character of these changes depends on the sample nature. In the shaped polysilicon the irradiation leads to both the increase of the GB recombination activity and the local decrease of EBIC, but in the CZ-silicon samples with microdefects it leads to the formation of fields with an increased EBIC value. The mechanism of the observed effect is discussed.