Mechanism of neutron- and electron-irradiation-induced phenomena of negative capacitance in NPN-BJT

The effects of neutron irradiation and electron irradiation on Si NPN-BJT (bipolar junction transistor) were investigated. After neutron irradiation and electron irradiation, the diffusion capacitance of transistor degraded, and even the negative capacitance(NC) phenomenon occurred. After electron irradiation, the barrier capacitance of transistor degraded, but it did not after neutron irradiation. A detailed analysis was made on the degradation mechanism of the junction capacitance after neutron irradiation and electron irradiation. The results indicate that, the defect is the cause of degradation. The defect clusters in transistor induced by both irradiations show as recombination centers, which greatly reduce the concentration and lifetime of minority carriers, giving rise to a serious