This invention relates to a microelectronic device comprising: a first support, a second support, first respective faces of the first support and second support being arranged opposite, and a sealing layer between said first faces, characterized in that the sealing layer comprises at least one layer of an ionic conductive material of formula LixPyOzNw, with x strictly greater than 0 and less than or equal to 4.5, y strictly greater than 0 and less than or equal to 1, z strictly greater than 0 and less than or equal to 5.5, w greater than or equal to 0 and less than or equal to 1.