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As the core component of the electron-bombarded active pixel sensor (EBAPS), the electron-sensitive CMOS (e-CMOS) can be prepared by thinning the surface layer of back-illuminated CMOS (BSI-CMOS), which was named electron sensitization. Due to the dramatic increase of dark current during the electron sensitization of BSI-CMOS, the signal-to-noise ratio and gain characteristics of the prepared EBAPS would be reduced. To solve this problem, this paper proposed a passivation strategy of SiO2 grown by plasma-enhanced chemical vapor deposition (PECVD) to inhibit surface defects, and the optimal SiO2 film thickness was explored through process optimization and electron bombardment system testing. As a result, the dark current was effectively suppressed (~50 e-1/s/pix), and a lower electron-sensitive threshold voltage of 550V was realized. Moreover, the defect states density of SiO2 deposited by PECVD was lower compared to Al2O3, which resulted from the more matched lattice coefficient of SiO2. Finally, EBAPS based on SiO2 passivated e-CMOS was realized, and high-quality imaging was successfully achieved at 1×10-4lx illumination. The above results showed that the SiO2 grown by PECVD can effectively suppress dark current at a thickness of ~5 nm, and reduce the electron-sensitive threshold voltage to 550 V, which provided technical support for the subsequent development of EBAPS devices with high gain and low noise.
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