Abstract: Thermoprocessing of integrated-circuit devices and ionizing radiation environments create electronic charges in dielectric isolation materials and in dielectric-semiconductor interface regions. These charges can produce serious alterations in the operating characteristics of the devices and integrated circuits. The deleterious effect of these charges may be greatly reduced by the disclosed process which produces a single-crystal silicon film dielectrically isolated from a polycrystalline silicon support by an underlying insulator of either silicon nitride or silicon dioxide, both of which may be grown by the process at selected locations on the same chip.