Fast neutron radiation effects in silicon detectors fabricated by different thermal oxidation processes

High resistivity silicon detectors along with MOS capacitors made on five silicon dioxides with different thermal conditions (975°C to 1200°C) have been exposed to fast neutron irradiation up to the fluence of a few times 10¹⁴ n/cm². New measurement techniques such as capacitance-voltage of MOS capacitors and current-voltage and back-to-back diodes (p⁺-n^--p ⁺ if n^- is not inverted to p) or resistors (p⁺-p-p⁺ if inverted) have been introduced in this study in monitoring the possible type-inversion (n→p) under high neutron fluence. No type-inversion in the material underneath SiO₂ and the p⁺ contact has been observed for detectors made on the five oxides up to the neutron fluence of a few times 10¹³ n/cm². However, it has been found that detectors made on higher temperature oxides (⩾1100°C) exhibited less leakage current increase at high neutron fluence