高能电子照射绝缘样品的泄漏电流特性

Leakage current characteristics of the insulating sample under high-energy electron irradiation

建立了考虑电子散射、输运、俘获和自洽场的数值计算模型,研究了高能电子束照射下绝缘厚样品的泄漏电流特性,并采用一个实验平台测量了泄漏电流.结果表明:在电子束持续照射下,电子总产额会下降;由于电子在样品内部的输运,样品近表面呈现微弱的正带电,在样品内部呈现较强的负带电;样品内部电子会向下输运形成电子束感生电流,长时间照射下会形成泄漏电流;随着照射,泄漏电流逐渐增大并趋于稳定值;泄漏电流随样品厚度的增大而减小,随电子束能量、电子束电流的增大而增大.

The leakage current characteristics of an insulating sample under high-energy electron beam irradiation are simulated by a numerical model with taking into account the electron scattering, transport, trapping and self-consistent field.The leakage current is measured by using a detection platform. Results show that under the continuous electron beam irradiation, the total electron yield decreases evidently; because of electron transport, the sample near the surface is positively charged weakly and its interior is negatively charged strongly; some electrons are transported downward, forming the electron beam induced current and the leakage current under the long time irradiation. Under the irradiation, the leakage current increases to a stable level gradually. The leakage current decreases with the increase of sample thickness, but it increases with beam energy and current.