Aside from having very good optical properties, the good ARC needs passivation effect (Si dangling bonds reduced) and thermal stability (during the firing of screen-printed metal contact). SiNx and SiO2 are the most popular films as ARC and have been applied on the silicon solar cell for a long time. In order to prevent disadvantage like thermal degradation and combine the benefits (low reflectance, and good passivation) of the SiNx and SiO 2, the ARC was modified to incorporate a thermally grown thin SiO2 layer beneath the PECVD SiNx. The SiO2/SiNx double layer ARC has a better output performance in particular Voc and FF than SiNx single layer. The Si/SiO2 interface is grown into the silicon crystal at a relatively high temperature, and the subsequent very effective hydrogenation of dangling bond interface states during the SiNx deposition. The gain of FF is predicted due to fewer hole defects in the SiO2/SiNx double ARC layer. The surface passivation by thermally grown SiO2 and PECVD SiNx double ARC is more effective than the SiNx single layer. Adding only a short oxidation process, we can have a +0.4% improved conversion efficiency of screen-printed mc-Si solar cell.