Optimization of the Transient Characteristics of the Rectifiers under High-Energy Electron Irradiation

It is shown that capacitance–frequency characterization can help to derive the optimization limits for radiation optimization of the transient properties of the rectifiers. Measurements of the current–voltage, capacitance–voltage, capacitance–frequency characteristics, and reverse recovery profiling were provided for silicon-based rectifiers. p–n-junction rectifiers were irradiated by 5 MeV electrons with fluences from 10¹⁴ to 10¹⁵ cm^–2. It is shown that reverse-recovery time decreases after 5 MeV electron irradiation and this decreasing changes monotonously with irradiation dose (from 2.2 ms to 15 µs for 10¹⁵ cm^–2). At the same time, series resistance increases dramatically (from 0.5 to 90 Ω); it indicates strong degradation of the high-frequency properties. Next criteria for optimal radiation dose can be used: the irradiation level associated with the maximum of boundary frequency indicates the optimum in terms of switching speed. Before this dose, maximum frequency is limited by reverse-recovery time of diode. After this dose, the limiting factor is the relaxation time of RC-circuit, where R is the series resistance of the diode and C is the capacitance of the SRC-region.