重掺杂直拉硅单晶的氧化诱生层错

发布时间：2018-04-16 09:24

本文选题：氧化诱生层错 + 重掺n型直拉硅　；参考：《浙江大学》2015年硕士论文

【摘要】：氧化诱生层错(OSF)是硅片在热氧化过程中可能产生的一种缺陷,它的存在会增大漏电流、降低击穿电压,导致器件性能下降甚至失效。目前,轻掺直拉硅单晶的OSF已经得到系统的研究,但对于重掺直拉硅单晶的OSF研究还不够深入和全面,尤其是重掺n型直拉硅单晶。相比于重掺p型,重掺n型直拉硅单晶的OSF的形成规律更为复杂。因此,系统研究重掺n型直拉硅单晶的OSF行为对全面深入理解OSF具有十分重要的意义。本论文研究了重掺n型直拉硅片的OSF的形成及动力学特性,并探讨了掺杂剂类型、形核中心、热处理气氛等因素对OSF行为的影响,取得了如下主要结果：1.研究了不同掺杂类型和不同掺杂浓度的重掺n型直拉硅片的OSF的行为。发现电阻率适中的重掺n型直拉硅片可以形成OSF,而当电阻率低至一定值(如小于5mΩ·cm)时,即使引入高密度的形核中心,重掺n型直拉硅片也难以产生OSF。2.研究了重掺磷和重掺锑直拉硅片引入不同类型及密度的形核中心所形成的OSF。结果表明,两种重掺n型直拉硅片的OSF密度显著受到形核中心影响,即高密度的形核中心导致高密度的OSF形成。然而OSF的长度却与其形核中心的密度及类型无关。3.对比研究了重掺锑和重掺磷直拉硅片的OSF的生长及收缩过程,以揭示掺杂剂对重掺n型直拉硅片的OSF的动力学的影响。研究表明：在相同的热氧化条件下,重掺锑直拉硅片的OSF的长度大于重掺磷的,且其生长激活能更低。基于密度泛函理论的第一性原理计算结果表明：与磷原子相比,锑原子是更有效的空位俘获中心,从而抑制空位与自间隙硅原子的复合。因此,在经历相同的热氧化时,氧化产生的自间隙硅原子与空位复合后所剩余的数量在重掺锑硅片中的更多,从而导致OSF更长。4.掺杂剂类型对重掺n型直拉硅片的OSF收缩行为没有明显的影响,但氮气氛会显著抑制OSF的收缩,其原因是在高温热处理中硅表面形成的氮化硅膜抑制了表面重构,减缓了OSF周围自间隙硅原子的发射。在惰性气氛的高温热处理过程中,氧化膜的存在会导致硅表面的自间隙硅原子向氧化膜中的回扩散,加快自间隙硅原子的发射,促进OSF的收缩；然而在氮气氛中热处理,由于氮化层会阻碍回扩散过程,OSF的收缩反而会受到抑制。
[Abstract]:Oxide induced stacking fault (OSF) is a possible defect in the thermal oxidation process of silicon wafer. Its existence will increase leakage current, reduce breakdown voltage, and lead to device performance decline or even failure.At present, the OSF with light Czochralski single crystal has been systematically studied, but the study of OSF for heavily Czochralski single crystal is not thorough and comprehensive enough, especially for the heavily doped Czochralski silicon single crystal.Compared with the heavily doped p-type, the formation of OSF in n-doped Czochralski single crystals is more complex.Therefore, the systematic study of the OSF behavior of n-doped Czochralski single crystals is of great significance for the thorough understanding of OSF.In this paper, the formation and kinetic characteristics of OSF for heavily doped n-type Czochralski wafers are studied, and the effects of dopant type, nucleation center and heat treatment atmosphere on the OSF behavior are discussed. The main results are as follows: 1.The behavior of OSF on n-type Czochralski wafers with different doping types and different doping concentrations was studied.It is found that heavy doped n-type Czochralski wafers with moderate resistivity can form OSFs, but when the resistivity is as low as 5 m 惟 cm, it is difficult to produce OSF.2when the high density nucleation center is introduced into the heavy doped n-type Czochralski wafers.The OSF formed by the introduction of different types and densities of nucleation centers on heavily doped and heavily doped antimony Czochralski wafers were investigated.The results show that the OSF density of two kinds of heavily doped n-type Czochralski wafers is significantly affected by the nucleation center, that is, the high density nucleation center leads to the formation of high density OSF.However, the length of OSF has nothing to do with the density and type of nucleation center.The growth and shrinkage process of OSF on heavy antimony doped silicon wafer and heavily doped phosphorus Czochralski silicon wafer were studied in order to reveal the effect of dopant on the OSF kinetics of heavily doped n-type Czochralski wafer.The results show that under the same thermal oxidation conditions, the length of OSF of heavy antimony doped Czochralski silicon wafer is longer than that of heavily doped silicon wafer, and its growth activation energy is lower.The results of first-principle calculations based on density functional theory show that antimony atoms are more effective vacancy trapping centers than phosphorus atoms and thus inhibit the recombination of vacancies with self-interstitial silicon atoms.Therefore, after the same thermal oxidation, the residual amount of self-interstitial silicon atoms recombined with vacancies is more than that of heavily antimony doped silicon wafers, resulting in a longer OSF. 4.The type of dopant has no significant effect on the shrinkage behavior of OSF on n-type Czochralski wafer, but nitrogen atmosphere can significantly inhibit the shrinkage of OSF, because the silicon nitride film formed on the surface of Si during high temperature heat treatment inhibits the surface reconstruction.The emission of self-interstitial silicon atoms around OSF is slowed down.In the process of high temperature heat treatment in inert atmosphere, the existence of oxide film will lead to the rediffusion of self-interstitial silicon atoms into the oxide film, accelerate the emission of self-interstitial silicon atoms and accelerate the contraction of OSF.However, the contraction of OSF will be inhibited because nitrided layer will hinder the rediffusion process.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.12

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