Investigation of discharge regimes of silicon needle with short air gap

Semiconductor electronic devices are prone to charge accumulation during production and transportation, which usually causes device breakdown. Ionizers are widely used for electrostatic elimination, and utilizing semiconductor silicon for the discharge needle material in ionizers can effectively prevent metal contamination. To investigate the discharge characteristics of silicon needles and their mode modulation mechanism, this study has established an experimental platform for silicon needle-plate discharge under positive polarity voltage. Discharge pulse parameters and optical signals were measured at varying electrode spacings. The experimental results reveal that silicon needle discharge progresses through four regimes: the spontaneous streamer, the periodic streamer, the cluster streamer, and the glow discharge. Among these, the pulse amplitude is most uniform and stable in the periodic streamer regime. In addition, shorter-gap discharge exhibits higher pulse amplitude and repetition frequency but is easier to transition into the filament regime. The formation process of a single pulse is closely related to the field strength in the ionization region near the needle tip. Hence, parameters such as the pulse rising edge time and falling edge time show minimal variation with voltage. The amount of charge generated per unit time is primarily influenced by the repetition frequency. Consequently, the electrostatic ionizer produces the highest, most stable, and most uniform charges if it operates in the periodic streamer regime.