NOVELTY - Forming an aluminum oxide (Al2O3)/silicon dioxide (SiO2) stack comprises: providing a substrate; injecting silicon containing compound, through an atomic layer deposition (ALD) process; injecting an oxygen source; reacting the silicon containing compounds and oxygen source to obtain the SiO2 layer deposited onto substrate; injecting aluminum containing compound dimethylaluminum isopropoxide on the SiO2 film through an ALD process; injecting the oxygen source; and reacting aluminum containing compounds and oxygen source to obtain the Al2O3 layer deposited onto SiO2 layer issued.    USE - The method is useful for forming an aluminum oxide and silicon dioxide stack, and passivation of photovoltaic devices, preferably solar cells (all claimed).    ADVANTAGE - The method is capable of effectively and economically forming an aluminum oxide and silicon dioxide stack with good chemical passivation capabilities.    DETAILED DESCRIPTION - Forming an aluminum oxide (Al2O3)/silicon dioxide (SiO2) stack comprises: (a) providing a substrate into a reaction chamber; (b) injecting at least one silicon containing compound comprising bis(diethylamino)silane, bis(dimethylamino)silane, bis(ethylmethylamino)silane, (di-isopropylamido)silane and (di tert-butylamido)silane, through an atomic layer deposition (ALD) process into the reaction chamber; (c) injecting an oxygen source comprising oxygen, ozone, oxygen plasma, water, carbon dioxide plasma and nitrous oxide plasma into the reaction chamber; (d) reacting at least one of the silicon containing compounds and the oxygen source into the reaction chamber at a temperature of 20-400 degrees C, preferably less than or equal to 250 degrees C, to obtain the silicon dioxide layer deposited onto the substrate; (e) injecting at least one aluminum containing dimethylaluminum isopropoxide on the silicon oxide film through an ALD process; (f) injecting the oxygen source; and (g) reacting at least one of the aluminum containing compounds and the oxygen source into the reaction chamber at a temperature comprised 20-400 degrees C, preferably less than or equal to 250 degrees C, to obtain the Al2O3 layer deposited onto the SiO2 layer issued of step (d). An INDEPENDENT CLAIM is included for Al2O3/SiO2 stack obtained by the method.