A novel approach for detecting negative charge accumulation induced by electron beam irradiation using power MOSFET devices

Micro-discharging and electrostatic discharges, caused by secondary electron emission and other factors, can severely impact spacecraft and vacuum equipment. Therefore, electrostatic protection is essential for their safe and reliable operation. This paper presents a quantitative method for detecting surface charge accumulation from electron beam irradiation using power MOSFETs, enabling the controlled release of accumulated charges for electrostatic protection. First, a response model was developed for the drain-to-source voltage of MOSFETs based on gate charge accumulation from electron beam irradiation. The study investigated the charge response of four device types: N-channel depletion/enhancement and P-channel depletion/enhancement MOSFETs. Based on this, a dual-model test system for charge accumulation detection and electrostatic discharge protection was designed, with an external capacitor to adjust the charge accumulation-discharge threshold, offering flexibility for various applications. Quantitative measurement of charge accumulation under 30 keV electron beam irradiation was conducted in the scanning electron microscope chamber, with a charge-discharge pulse precision of 3.27 nC. The measurement system can be calibrated using the actual incident beam current measurement results, with the charge accumulation rate measurement error being less than 0.15 nC/s. This research contributes to a measurement system based on a novel approach for electrostatic detection and controllable discharging, which can accurately detect weak charging and dynamically monitor the charge accumulation rate. It provides an innovative concept for electrostatic protection design.