NOVELTY - A silicon wafer-based solar cell with a two-layer antireflective coating on its surface which is oriented to light during operation of the cell, comprises a hydrogen containing silicon passivation layer followed by a niobium oxide NbxOy layer and a cover having a refractive index of 1.5. The hydrogen containing silicon passivation layer is a hydrogenated silicon nitride SixNy:H layer; and has a thickness of 10-30 nm. The niobium oxide comprises Nb2O5. The cover comprises glass or ethylene vinyl acetate.    USE - As a silicon wafer-based solar cell (claimed).    ADVANTAGE - The SiN:H film thickness of 10-30 nm offers sufficient passivation without too much degrading the optical properties by low-wavelength absorption. The resulting double layer antireflective coating (ARC) provides significantly enhanced solar module efficiency due to improved optical properties. Compared to TiO2 the niobium oxide reactive sputtering process is less dependent on the exact stoichiometry of the resulting film (especially when minimal low-wavelength absorption is mandatory), and also sputter rates for Nb2O5 are two to five times higher compared to TiO2. Both layers are deposited in the very same single wafer multi chamber sputtering tool for optimized throughput and cost considerations. The Nb2O5 layer is deposited in hydrogen containing gas atmosphere for improved hydrogen incorporation into the Si wafer as well as the Si/ARC interface after furnace firing. The Nb2O5 is deposited only after the front and back contacts have been deposited (e.g. by screen printing) and contact has been established (e.g. by furnace firing of front- and backside paste).    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for manufacturing the silicon wafer-based solar cell with a two-layer antireflective coating, involving: depositing a hydrogen containing silicon passivation layer on a surface of a wafer-based silicon solar cell, the surface to be oriented to light during operation of the cell; followed by depositing a niobium oxide NbxOy layer; and attaching a cover having a refractive index of 1.5 onto the niobium oxide layer, where the passivation (SixNy:H) layer is deposited either by plasma enhanced chemical vapor deposition (PECVD) or by reactive sputtering (PVD) from a Si target with N2 and/or NH3, and niobium oxide (Nb2O5) layer is deposited by reactive sputtering of either a pure Nb target or a conductive Nb2Ox (x less than 5) target with O2, and both layers of the two-layer antireflective coating are deposited subsequently in one single wafer multi chamber sputtering tool.    DESCRIPTION OF DRAWING(S) - The figure shows a basic view of a layer sequence.