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轻掺杂多晶硅的低温退火特性揭示了来自二氧化硅层中的氧对多晶硅电学行为有重要影响。本文从实验上进一步证实了氧在多晶硅晶界引入可变的载流子俘获能态,定性分析了氧俘获态随处理温度和时间的变化关系;论证了在杂质分凝效应中起主要作用的是氧俘获态,实际分凝效果比理论值和表观测量值小得多。文章对多晶硅晶界的某些性质提出了新的看法,指出晶界俘获态密度并不完全是多晶硅自身固有的和具有固定不变的数量,氧在晶界引入的可变俘获态是决定轻掺杂多晶硅电导能力的主要因素,氧在晶界可能只引入电子俘获态。这个物理模型能够合理解释轻掺杂多晶硅许多不同于重掺杂多晶硅的电学行为。
The low temperature annealing of lightly doped polycrystalline silicon reveals that oxygen from the silicon dioxide layer has a major influence on the electrical behavior of polycrystalline silicon. In this paper, we further confirm that oxygen introduces a variable carrier trapping energy state at the polycrystalline silicon grain boundaries. The relationship between the oxygen trapping state and the processing temperature and time is qualitatively analyzed. It is demonstrated that the oxygen species plays a major role in the segregation of impurities Is the oxygen capture state, the actual sub-condensate effect is much smaller than the theoretical and apparent measurements. In this paper, we propose a new view on some properties of polycrystalline silicon grain boundaries. It is pointed out that the density of grain boundary trapping states is not completely intrinsic and constant to polycrystalline silicon. The variable trapping state introduced by oxygen at grain boundaries is determined by the light Doped polysilicon conductivity of the main factors, oxygen in the grain boundary may only introduce electronic capture state. This physical model can reasonably explain many of the electrical behaviors of lightly doped polysilicon that differ from heavily doped polysilicon.