Chemical bonding method and joined structure

A chemical bonding method in which substrates to be bonded are two substrates composed of the same materials or a combination of different materials, selected from pure metals, alloys, or Si, comprising, in a vacuum vessel, forming amorphous oxide thin films having a state of oxygen deficiency or supersaturated oxygen compared to stoichiometric composition on bonding surfaces of the two substrates each having the bonding surface by magnetron sputtering involving quenching of raw material atoms on the bonding surfaces,

• during formation of the amorphous oxide thin films, the number of vacancy defects inside the films being increased by controlling the oxygen deficiency or the supersaturated oxygen whereby increasing atomic mobility, and following the formation of the amorphous oxide thin films, superimposing the two substrates so that the amorphous oxide thin films formed on the two substrates are in contact with each other,
• whereby causing movement of atoms at a bonding interface between the amorphous oxide thin films by the increased atomic mobility of the amorphous oxide thin films in which the number of the vacancy defects inside the films is increased, and
• thereby causing chemical bonding involving atomic diffusion at the bonding interface to bond the two substrates.