衝擊離子化效應受金氧半場效電晶體微縮之影響

Impact Ionization Phenomenon in MOSFET Scaling

詹國志(Kuo-Chih Chan) ； 陳俊佑(Chin-Yu Chen) ； 江孟學(Meng-Hsueh Chiang)

《國立宜蘭大學工程學刊》 5期 (2009/03) Pp. 49-64

https://doi.org/10.6176/BCE.2009.05.14

摘要

拜半導體技術一日千里之賜，電晶體尺寸持續縮小，造成元件通道間之電場隨著快速上升，此時與高電場有關之效應也就越來越重要。當電子經過通道時被電場加速，進一步導致晶格碰撞，如電子能量夠大將產生成對的電子與電洞。本篇論文重點在於衝擊離子化效應受金氧半場效電晶體微縮之影響，透過不同的物理模型之三維數值模擬，分別針對溫度、摻雜濃度、通道長度及閘極絕緣層厚度的變化做特性分析。我們發現在不同通道長度下的元件，其衝擊離子化效應受溫度的影響大不相同，尤其當更精確的考慮能量平衡的效應時，所得到的溫度敏感度與傳統的載子傳輸結果卻相反。在衝擊離子化影響日益顯著的情況下，這些研究成果對未來先進元件的持續微縮工作極具參考價值。

關鍵字

衝擊離子化 ； 晶格碰撞 ； Chynoweth model ； Valdinoci model ； 能量平衡

並列摘要

High field effects have become significant as the transistor Size, driven by fast technology progress, continues to scale. Among high field effects, impact ionization due to hot carriers is one of major issues in scaled devices. In this paper, we investigate such effect in ultra-scaled SOI MOSFETs. Effects of impact ionization in different doping levels, oxide thicknesses, and channel lengths are evaluated via 3D numerical simulations with different physical models. Furthermore, the dependence of impact ionization on temperature is comprehensively analyzed. When energy balance is taken into account, the temperature dependence becomes opposite to the case with conventional drift and diffusion transport. As implied by the physical insight, impact ionization would be inevitable and even more substantial for ultra-scaled devices operated at elevated temperature.

並列關鍵字

impact ionization ； lattice scattering ； Chynoweth model ； Valdinoci model ； energy balance