Temperature dependence of bipolar junction transistor current-voltage characteristics after low dose rate irradiation

Temperature variation on board can have a significant impact on electronic circuit parameters. In this paper, we investigate and model how both irradiated NPN and PNP-Bipolar Junction Transistors (BJTs) at room temperature respond electrically to temperature variation. A temperature-dependent analytical model for total-ionizing-dose-induced excess base current in BJTs is proposed. Our model captures base current dependence on temperature on irradiated parts. To do so, the devices under test are irradiated at room temperature with all terminals grounded. After irradiation, base currents are obtained, and the concentrations of oxide defects (i.e., oxide trapped charge and interface traps) created during irradiation are calculated. At the end, results from our analytical model and experimental data are compared to SPICE simulations. Both base current and defect densities resulting from room temperature irradiations are used as inputs to SPICE simulations and the analytical model. Experimental data obtained from measurements at both low and high temperatures on parts irradiated at room temperature are shown to compare well to the simulation results and analytical model over a range of temperatures. The modeling work shows that SPICE simulations can support qualification for commercial-off-the-shelf (COTS) linear bipolar components with temperature for space applications.