NOVELTY - Making aluminum oxide/silicon dioxide stack comprises: (a) providing substrate into a reaction chamber; (b) injecting silicon containing compound into the chamber by atomic layer deposition process; (c) injecting an oxygen source into the chamber; (d) reacting the silicon containing compounds and oxygen source at 20-400 degrees C, preferably less than or equal to 250 degrees C to obtain silicon dioxide layer deposited onto substrate; (e) injecting aluminum containing compound on silicon oxide film; (f) injecting oxygen source; and (g) reacting aluminum containing compounds and oxygen source at 20-400 degrees C, preferably less than or equal to 250 degrees C.    USE - The stack is useful for the passivation of photovoltaic devices, preferably solar cells (claimed).    ADVANTAGE - The method provides the aluminum oxide/silicon dioxide stack in reduced manufacturing costs with reduced raw materials consumption. The stack provides the photovoltaic cells with improved efficiency.    DETAILED DESCRIPTION - Forming an aluminum oxide/silicon dioxide stack comprises: (a) providing a substrate into a reaction chamber; (b) injecting at least one silicon containing compound consisting of bis(diethylamino)silane (BDEAS), bis(dimethylamino)silane (BDMAS), bis(ethylmethylamino)silane (BEMAS), (di-isopropylamido)silane (DIPAS) or (di-tert-butylamido)silane (DTBAS), into the reaction chamber through an atomic layer deposition (ALD) process; (c) injecting an oxygen source comprising oxygen, ozone, oxygen plasma, water, carbon dioxide plasma or nitrogen oxide plasma, into the reaction chamber; (d) reacting at least one of the silicon containing compounds and the oxygen source at 20-400 degrees C, preferably less than or equal to 250 degrees C, into the reaction chamber in order to obtain the silicon dioxide layer deposited onto the substrate; (e) injecting at least one aluminum containing compound as trimethylaluminum or trimethylaluminum, on the silicon oxide film through the ALD process; (f) injecting the oxygen source; (g) reacting the aluminum containing compounds and the oxygen source at 20-400 degrees C, preferably less than or equal to 250 degrees C, into the reaction chamber in order to obtain the aluminum oxide layer deposited onto the silicon dioxide layer. An INDEPENDENT CLAIM is also included for the aluminum oxide/silicon dioxide stack obtained by the method.