Overview on crystalline silicon solar cells using PECVD rear passivation and laser-fired contacts
Solar cells of "classic" external contact structure with front and rear contacts applying a passivated and locally contacted rear are presented in this paper. A variety of rear surface passivation schemes deposited by PECVD are discussed and compared using illuminated I-V, reflection and internal quantum efficiency measurements with fixed and variable bias light intensities. All cells presented were contacted on the rear by laser-firing. It is shown that amorphous hydrogenated silicon (a-Si) stacked with amorphous hydrogenated silicon oxide (SiOx) is reaching a comparable level of rear surface passivation as thermally grown silicon dioxide (SiO2) and that the bias-light dependence of such cells is lower than that of SiO2 or amorphous hydrogenated silicon nitride (SiNx) stacked with SiOx passivated cells. Additionally, firing stable stacks of SiOx, SiNx and SiOx are compared to SiCx and the above mentioned layer systems.