Random reactive ion etching texturing techniques for application of multicrystalline silicon solar cells

Abstract

To maximize the conversion efficiency of solar cells by improving the trapping of incident light, surface texturing of multicrystalline silicon wafers is a more permanent and effective solution to decrease reflections compared with antireflection coatings. In general, many techniques of wet chemical surface texturing depend on crystal orientation. Also, these processes place a limitation on the growth of solar production capacity due to consumption of the large amount of material, de-ionized water and chemicals. Reactive ion etching (RIE) is therefore useful for mc-Si solar cells with the random grain orientation. In this study, we have fabricated mc-Si solar cells with a large-area (156mm×156mm) by a random RIE texturing method using SF6/O2 plasma chemistry. A large amount of silicon loss, which is due to saw damage removal and texturing process of mc-Si wafers, have dramatically decreased by applying RIE texturing process. As a result of the optimum RIE process, the best mc-Si solar cell showed conversion efficiency, fill factor, short circuit current density, and open circuit voltages as high as 17.4%, 80%, 35mA/cm2 and 620mV, respectively. This study demonstrates that it is possible to apply the thin mc-Si Solar cells fabrication for low cost and high efficiency in conventional industrial production line.