Passivation by a dielectric layer on the top of crystalline silicon (c-Si) wafer, also called "tunnel passivation" is one of the passivation techniques used most widely in PV technology. This technique combines both chemical passivation and field-effect passivation. This strategy is based on the formation of a dielectric layer (mostly silicon dioxide SiO 2, aluminum oxide Al 2 O 3, or silicon nitride (SiN x) on the top of the c-Si substrate be the mean of thermal oxidation or other deposition techniques such as atomic layer deposition (ALD). In the case of the formation of SiO x by thermal oxidation, the process acts as chemical passivation since, on the one hand, the formation of the oxide layer reacts with the dangling bonds on the surface wherein it reduces the defects states at the interface. On the other hand, since there are fixed charges (Q f) in the dielectric film, these fixed charges establish an electric field that repels one type of charge carrier and accumulates the other type at the interface. This repletion assures reducing one type of the charge carriers concentration at the interface wherein the recombination decreases.