We have examined the microstructure and the transport properties of nitrogen-implanted silicon-on-insulator wafers, as well as the performance of integrated-circuit transistors fabricated in this material. The insulating regions were fabricated in silicon by the unpatterned implantation of 4×1017 /cm2, 300 keV nitrogen dimers followed by annealing at 1473 K for 5 hours. For these parameters, the buried nitrogen-implanted layer crystallized into α-silicon nitride, and contains ≈20% excess silicon in the form of silicon inclusions of 5–15 nm diameter. The surface silicon layers are characterized by low-mobility, p-type conduction. The buried dielectric has a resistivity of approximately 108 Ωcm. Functional p-channel, integrated circuit transistors have been fabricated in n-type epitaxial silicon grown over the buried-nitride wafers. These transistors devices are similar in performance to those fabricated in bulk silicon,(hole mobilities in inversion layers of 140 cm2/V-s), and demonstrate the suitability of the buried nitride process for integrated circuit applications.