Time-dependent radiation-induced charge effects in wafer-bonded SOI buried oxides

Time-resolved capacitance-voltage [C(V_g )] voltage shift measurements were performed on wafer-bonded and etched-back silicon-on-insulator (BESOI) buried oxide (BOX) capacitors following their exposure to pulsed irradiation. The results indicate that BESOI BOX, in some cases, more closely resembles thick thermal SiO ₂ than SIMOX (separation by implantation of oxygen) BOX, and shows substantial hole transport and only moderate bulk hole trapping. However, unlike conventional thermal oxides, the BESOI BOX shows evidence of electron trapping in the oxide probably associated with the wafer bonding interface. High-temperature annealing reduces the electron trapping but enhances hole trapping at the Si-SiO₂ interfaces and possibly in the BOX bulk. The results indicate that location of the bonding surface and control of high-temperature annealing are important for producing radiation-hard BESOI