Method of direct bonding between two plates, comprising a step of forming a temporary protective layer has a nitrogen base

To avoid problems of hydrolysis of the silicon oxide formed by PECVD on the surface of at least one plate, it is proposed to cover, in the chamber of vacuum deposition used for the deposition of silicon oxide , said oxide by a temporary protective layer comprising nitrogen. The protective layer, protecting thus the silicon oxide against the external environment and in particular of moisture, when the plate provided with the silicon oxide is stored out of the vacuum deposition chamber. The protective layer is subsequently removed, for example by chemical mechanical polishing, just before contacting the two plates. The protective layer may be formed by a PECVD deposition of silicon nitride by plasma nitriding or nitrogen doping a surface portion of the silicon oxide.