NOVELTY - Preparation of dielectric barrier layer of silicon oxide on substrate, involves depositing layer (21) of silicon oxide (I) using plasma-enhanced chemical vapor deposition method on substrate (1). In deposition of layer (22) of silicon oxide (I), mixture of methyltriethoxysilane, tetraethyl orthosilicate, N,N'-dimethylformamide and orthophosphoric acid is formed. The condensation-hydrolysis of obtained mixture is carried out in constant agitation condition. The coating composition is deposited and densified by evaporating solvent, to form dielectric barrier layer of silicon oxide.    USE - Preparation of dielectric barrier layer of silicon oxide (claimed) used for photovoltaic solar cell module.    ADVANTAGE - The method enables efficient and economical preparation of dielectric barrier layer of silicon oxide having excellent functionality.    DETAILED DESCRIPTION - Preparation of dielectric barrier layer of silicon oxide on substrate, involves cleaning and drying the substrate, depositing a layer (21) of silicon oxide of formula: SiOx (I), where x is 0.5-2, using plasma-enhanced chemical vapor deposition method, using precursor gas of silicon and oxygen gas precursor, and depositing layer (22) of silicon oxide (I) using sol-gel method. The deposition of layer of silicon oxide (I) using sol-gel method involves forming a coating composition containing 30-50 wt.% methyltriethoxysilane, 7-12 wt.% tetraethyl orthosilicate, 11-19 wt.% N,N'-dimethylformamide, 19-31 wt.% polyethylene glycol, 7-12 wt.% distilled water, and 0.6-0.9 wt.% orthophosphoric acid, in which a mixture of methyltriethoxysilane, tetraethyl orthosilicate and N,N'-dimethylformamide are mixed, polyethylene glycol is added to the mixture, distilled water is added to the mixture and orthophosphoric acid is added to the obtained mixture. The condensation-hydrolysis of obtained mixture is carried out in constant agitation condition. The obtained coating composition is deposited and densified by evaporating solvent of the composition, to form dielectric barrier layer of silicon oxide.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of dielectric barrier layer of silicon oxide.    Substrate (1)    Deposited layer (2)    Layers of silicon oxide (21,22)