直拉硅单晶压痕位错的运动
发布时间：2018-12-17 09:12
【摘要】：作为集成电路的基础材料,直拉单晶硅的机械强度一直得到研究者关注。随着集成电路制造的光刻精度的提高,硅片的机械强度显得尤为重要。在很大程度上,位错在应力驱动下的滑移反映了硅片的机械强度。近十年来,共聚焦显微拉曼术已变得很成熟,而单晶硅具有特征的拉曼峰,其峰位对应力相当敏感。因此,可以利用共聚焦显微拉曼术定量地表征硅片的应力及其分布等,这为深入地研究单晶硅中的位错滑移与应力之间的关系提供了有利条件。本文利用共聚焦显微拉曼术研究了维氏压痕的残余应力与对位错滑移的影响,得到如下主要结果：(1)研究了不同浓度硼掺杂的直拉单晶硅片上维氏压痕位错的滑移行为,采用共聚焦显微拉曼术研究了压痕附近的应力分布情况。结果表明：随着掺硼浓度的提高,压痕附近的残余应力明显变小。此外,在经过900℃/2h的热处理后,电阻率为～1mΩ·cm的硅片上的压痕位错没有发生明显的滑移,而电阻率为～10mΩ·cm的硅片上的压痕位错则有较显著的滑移。这是由于高浓度的硼杂质对位错产生了明显的钉扎作用,从而抑制了位错的滑移。(2)研究了重掺和轻掺硼直拉单晶硅片压痕残余应力和位错滑移之间的关系,探讨了维氏压痕附近应力在热处理时释放的原因。结果表明：压痕在进行900℃高温热处理时,其附近残余应力的释放主要有两个原因：在热处理的前几分钟,其应力释放主要由于压痕残余的弹性形变的释放所致,此时压痕的残余应力急剧降低；在之后,位错的滑移是压痕附近残余应力变小的主要原因：残余应力随着位错的滑移而逐渐变小,如位错没有产生滑移,则残余应力保持不变。(3)采用共聚焦显微拉曼术研究了直拉单晶硅片上压痕的残余应力经过300℃或500℃热处理后的预释放,然后研究了应力预释放对压痕位错在后续较高温度(700℃-900℃)热处理过程中滑移的影响。结果表明：经过应力预释放后,压痕位错的滑移速率显著变小,后续热处理温度越低,滑移速率的减小幅度越大。但是,只要足够地延长后续热处理的时间,位错滑移的最大距离仍与未经预应力释放情形时的一样。因此,可以认为：在压痕的残余应力大于位错在某一温度滑移所需临界应力的前提下,压痕位错在某一温度滑移的最大距离与应力大小无关,只不过达到最大距离所需的时间随应力的减小而显著增长。
[Abstract]:As the basic material of integrated circuit, the mechanical strength of Czochralski silicon has been concerned by researchers all the time. With the improvement of lithography precision, the mechanical strength of silicon wafer becomes more and more important. To a large extent, the slip of dislocation driven by stress reflects the mechanical strength of silicon wafer. In recent ten years, confocal Raman microscopy has become very mature, while monocrystalline silicon has a characteristic Raman peak, and its peak position is very sensitive to stress. Therefore, confocal Raman microscopy can be used to quantitatively characterize the stress and distribution of silicon wafers, which provides a favorable condition for further study of the relationship between dislocation slip and stress in monocrystalline silicon. In this paper, the residual stress of Vickers indentation and its effect on dislocation slip are studied by confocal Raman microscopy. The main results are as follows: (1) the slip behavior of Vickers indentation dislocation on Czochralski silicon wafer with different concentrations of boron doping is studied. The stress distribution near indentation was studied by confocal Raman microscopy. The results show that the residual stress near the indentation decreases obviously with the increase of boron concentration. In addition, after heat treatment at 900 鈩，
本文编号：2384002
[Abstract]:As the basic material of integrated circuit, the mechanical strength of Czochralski silicon has been concerned by researchers all the time. With the improvement of lithography precision, the mechanical strength of silicon wafer becomes more and more important. To a large extent, the slip of dislocation driven by stress reflects the mechanical strength of silicon wafer. In recent ten years, confocal Raman microscopy has become very mature, while monocrystalline silicon has a characteristic Raman peak, and its peak position is very sensitive to stress. Therefore, confocal Raman microscopy can be used to quantitatively characterize the stress and distribution of silicon wafers, which provides a favorable condition for further study of the relationship between dislocation slip and stress in monocrystalline silicon. In this paper, the residual stress of Vickers indentation and its effect on dislocation slip are studied by confocal Raman microscopy. The main results are as follows: (1) the slip behavior of Vickers indentation dislocation on Czochralski silicon wafer with different concentrations of boron doping is studied. The stress distribution near indentation was studied by confocal Raman microscopy. The results show that the residual stress near the indentation decreases obviously with the increase of boron concentration. In addition, after heat treatment at 900 鈩，
本文编号：2384002
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