Electron trapping in irradiated SIMOX buried oxides

Presented are new results of X-ray exposure of silicon-on-insulator devices fabricated on SIMOX (separation by implantation of oxygen) substrates. It is shown that the presence of numerous electron traps in the buried oxide may dominate the back-gate threshold voltage shift of strongly irradiated SIMOX transistors. A rebound effect occurs under a negative oxide field, due to the trapping of negative charges rather than to interface states generation. Irradiated transistors also show an increased sensitivity to hot-carrier effects.>