To provide an SOI-wafer manufacturing method whereby the manufacturing of the SOI wafer by the lamination of the large-aperture wafers having diameters not smaller than eight inches causes no voids nor blisters, etc. not to occur in the joint interface between a base wafer and a silicon bonding wafer having its surface covered with an insulator, and such an SOI wafer having a strong gettering ability is manufactured simply at a low price.

The SOI-wafer manufacturing method is provided by joining a silicon bonding wafer having at least its surface covered with an insulator with a base wafer via an insulator. This method is characterized in that their lamination is made by joining the silicon bonding wafer with the base wafer via the joint interface comprising a bonding agent or film which has SiO2 as its main component and contains one or more kinds of boron, phosphorus, and nitrogen, and thereafter, by a heat-treating them.