Novel integrated circuits (SOI ICs), and methods for making and mounting the ICs are disclosed. In one embodiment, an IC comprises a first circuit layer of the IC formed from an active layer of an SOI wafer. The first circuit layer is coupled to a first surface of buffer layer, and a second surface of the buffer layer is coupled to a selected substrate comprising an insulating material. The selected substrate may be selected, without limitation, from the following types: sapphire, quartz, silicon dioxide glass, piezoelectric materials, and ceramics. A second circuit layer of the IC are formed, coupled to a second surface of the selected substrate. In one embodiment of a mounted IC, the first circuit layer is coupled to contact pads on a package substrate via solder bumps or copper pillars. The second circuit layer is coupled to contact pads on the package substrate via wire bonds.