在離子佈植設備中，Bushing 作為離子束傳輸與電場絕緣的關鍵部件，其表面長時間暴露於高電場與含毒性化學氣體（如砷 As、磷 P、硼氟 BF）環境下，容易產生局部放電、擊穿現象與氣體沉積效應，進而導致絕緣性能下降、設備維護頻率提升導致使用壽命縮短。為解決此問題，本研究提出於 bushing 內壁施加氮化矽（Si₃N₄）塗層，並採用數值方法進行電場分布模擬，探討塗層對局部放電與表面沉積機率的改善效果。
研究藉由建立具備與未具備氮化矽塗層之 bushing 三維幾何模型，並於高電壓邊界條件下進行靜電場模擬，系統性探討塗層之厚度與介電常數變化對整體電場分布與均化效應之影響。模擬結果顯示，塗佈氮化矽後可顯著抑制表面電場集中現象，降低峰值電場強度，從而有效削減局部放電產生的潛勢。此外，氮化矽塗層具備優異的表面能特性與低極性吸附傾向，有助於減緩含砷（As）、磷（P）與硼氟（BF）等離子態氣體在 bushing 內壁表面之吸附與化學沉積現象。此抑制效應有助於減少污染層生成速率，延緩絕緣性能劣化，進一步提升離子佈植設備中 bushing 之與維護週期，對長期穩定運行具有實質貢獻。
研究結果表明，應用氮化矽塗層不僅能顯著改善高壓放電環境下的電場分布，亦具潛力有效降低反應性氣體附著，進一步延長 bushing 的使用壽命與設備保養週期，對提升離子佈植系統長期穩定運作具有實質助益。

In ion implantation systems, bushings are critical for ion beam transmission and electrical insulation. However, they are directly exposed to high electric fields and process gases such as arsine (AsH₃), phosphine (PH₃), and boron trifluoride (BF₃). These conditions promote partial discharge, dielectric breakdown, and surface contamination, which degrade their insulation performance and shorten service life. This study investigates the potential of using of silicon nitride (Si₃N₄) coating on the inner bushing surface to mitigate these problems.
Three-dimensional bushing models, with and without the coating, were analyzed numerically under high-voltage electrostatic conditions. The effects of coating thickness and dielectric constant on electric field distribution and surface charge were evaluated. The results show that Si₃N₄ coatings effectively mitigate electric field strength at critical regions and reduce peak field intensity, thereby lowering the probability of partial discharge. In addition, the coating’s favorable surface energy and low-polarity adsorption characteristics reduce the deposition of ionized species derived from arsine (AsH₃), phosphine (PH₃), and boron trifluoride (BF₃), slowing contamination layer growth and delaying insulation aging.
Overall, Si₃N₄ coating improves electric field uniformity and suppresses reactive-gas deposition, offering a practical approach to enhancing the long-term stability and reliability of ion implantation bushings.

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