Combined Effects of Transient Ionizing and Electromagnetic Pulse on Vertical NPN Bipolar Transistor

TL;DR

Examines how transient ionizing radiation (pulsed X-ray) and EMP interact with a vertical NPN transistor (2N2222A). Combines controlled experiments with TCAD simulations to show that X-ray plus CEMP yields a superlinear response due to enhanced drift and diffusion photocurrents at the collector, while X-ray plus BEMP largely follows BEMP alone. Mechanistic analysis attributes this to differences in transistor active region vs. saturation state under the two EMP injection modes. The work provides practical guidance for radiation-hardening bipolar circuits in extreme radiation environments, such as ICF facilities.

Abstract

Combined effects of transient ionizing and electromagnetic pulse on vertical NPN bipolar transistor were experimentally investigated under pulsed X-ray irradiation. Technology computer-aided design (TCAD) simulation method was also employed to explore the underlying physical mechanisms. The results demonstrate that the combined effect of a positive pulse injected into the collector (CEMP) and pulsed X-ray irradiation exceeds the linear superposition of their individual effects. Conversely, the combined effect of a positive pulse injected into the base (BEMP) and pulsed X-ray irradiation aligns closely with the results observed under BEMP acting alone. Mechanism analysis reveals that when CEMP and pulsed X-ray irradiation act simultaneously, there is a significant increase in both the drift photocurrent at the collector junction and the diffusion photocurrent near the collector junction. However, when BEMP and pulsed X-ray irradiation act simultaneously, these photocurrent components remain small, leading to a combined effect similar to the results observed when BEMP acts alone. These findings provide critical insights for the radiation-hardening design of bipolar circuits in harsh radiation environments.

Figures (16)

• Figure 1: Schematic diagram of various types of SGEMP generated during transient X-ray irradiation of electronic equipment.
• Figure 2: Bias configurations of the 2N2222A transistor under pulsed X-ray irradiation: (a) Combined effect of pulsed X-ray irradiation and pulse injected into the collector (CEMP); (b) Combined effect of pulsed X-ray irradiation and pulse injected into the base (BEMP).
• Figure 3: Experimental results of the secondary photocurrent response (${V}_{{SP}}$) under different biases (${V}_{{1}}$): (a) Waveform of ${V}_{{1}}$; (b) Transient voltage response at the emitter (${V}_{{SP}}$).
• Figure 4: Experimental results of the combined effects of pulsed X-ray irradiation and CEMP ($V_{1}$ = 30 V): (a) Waveform of ${V}_{{C0}}$; (b) Base voltage response (${V}_{{B}}$); (c) Emitter voltage response (${V}_{{E}}$).
• Figure 5: Experimental results of the combined effects of pulsed X-ray irradiation and BEMP ($V_{1}$ = 30 V): (a) Waveform of ${V}_{{B0}}$; (b) Base voltage response (${V}_{{B}}$); (c) Emitter voltage response (${V}_{{E}}$).