The radiation response of capacitors fabricated on bonded silicon-on-insulator substrates

Silicon-on-insulator substrates were manufactured by bonding a thermal oxide of silicon to a silicon wafer. Metal-oxide-silicon capacitors were fabricated on these substrates. Capacitors were also fabricated on unbonded thermal oxides. Capacitance-voltage measurements were performed on the bonded and unbonded oxides, before and after 10 keV X-ray irradiation. The flatband shift for the irradiated bonded oxide was nearly double that of the irradiated unbonded oxide. The radiation-induced shifts of the capacitance-voltage curves are shown to be related to the density differences between the bonded and unbonded oxides.