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系统研究了点缺陷对晶体硅中氧沉淀生成的影响,及点缺陷和氧沉淀对重掺硼直拉硅单晶p/p~+外延片中铜沉淀的影响.样品先在不同的气氛下进行1250℃/60 s快速热处理,随后在750℃/8 h+1050℃/16 h常规热处理过程中引入铜沾污.通过腐蚀结合光学显微镜研究发现,以O_2作为保护气氛时,p~+衬底中的沉淀密度较小,以Ar和N_2作为保护气氛时,重掺硼p~+衬底中生成了高密度的沉淀,且在上述所有样品的外延层中均无缺陷生成.研究认为,以O_2作为保护气时引入的自间隙硅原子(Si_I)可以抑制沉淀的形成,而以Ar和N_2作为保护气氛时引入的空位则会促进沉淀的生成,这是导致此差异的主要原因.另外,研究还发现,p/p~+外延结构能很好地吸除硅片中的铜杂质,从而保持了外延层的洁净.
The effect of point defects on the oxygen deposition in crystalline silicon and the effect of point defects and oxygen precipitation on copper precipitation in p / p ~ + epitaxial wafers of heavily boron-doped Czochralski silicon have been investigated systematically. , Followed by rapid thermal treatment at 1250 ℃ for 60 s followed by copper stain during the conventional heat treatment at 750 ℃ for 8 h and 1050 ℃ for 16 h.The results of corrosion and optical microscopy showed that when O2 was used as the protective atmosphere, When the Ar and N 2 gas were used as the protective atmosphere, high density precipitates were formed in the heavily boron doped p ~ + substrate and no defects were formed in the epitaxial layers of all the above samples. The self-interstitial silicon (Si_I) introduced by O_2 as the shielding gas can inhibit the formation of the precipitate, whereas the vacancy introduced by Ar and N_2 as the protective atmosphere can promote the formation of the precipitate, which is the main reason for this difference. The study also found that the p / p ~ + epitaxial structure can well absorb the copper impurities in the silicon wafer, thus keeping the epitaxial layer clean.