权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Positron annihilation spectroscopy in behavior of defects by chemical analysis of nano-space in solids

正电子湮没光谱通过固体纳米空间化学分析研究缺陷行为

基本信息

批准号：
11450321
负责人：
FUJINAMI Masanori
金额：
$ 8.45万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450321/
关键词：
positron nanospace defects electron momentum defect-impurity complex Doppler broadening oxygen silicon

项目摘要

The aim of this research project is to clarify the chemical state of vacancy-impurity complex defects, or nano-space, in solids. We have developed a coincidence Doppler broadening(CDB)method in positron annihilation spectroscopy. The positrons trapped at V-I complexes annihilate electrons due to impurity. Annihilation with core electrons gives larger Doppler shifts compared with valence electrons, so that it is possible to identify the impurity by analyzing the high electron momentum region. The CDB method improves the peak to background ratio in the annihilation spectrum to around 10^5 and fine structures due to core electrons from impurity atom can be discussed. In this project, the defects in Si implanted with various kinds of ions have been investigated.Firstly, it is found that the CDB spectrum for Si ion implanted Si is appropriate as the reference for the defect study in Si. Some characteristic structures due to V-O, V-F and V-H complexes appear in high momentum region in the CDB spectra. From the CDB spectra and positron lifetime, the defect behavior has been considered. For example, the defect induced by O implantation to Si is identified as V_3O, which is transformed into V_6O_2 in annealing at 600°C.An anneal at 800°C results in formation of V_<10>O_6.Further, we have studied the defects in Fe implanted with Cu ions. Simple vacancy-type defects are observed in the surface layer of the sample implanted with less than 5x10^<14>/cm^2, while it has been found that in 5x10^<15>/cm^2, the inner wall of voids is covered with Cu atoms. Combined with the positron lifetime measurement, CDB technique becomes a powerful tool for investigating the defect structure, especially vacancy-impurity complexes.

该研究项目的目的是阐明固体中空位-杂质复合缺陷或纳米空间的化学状态。本文发展了一种正电子湮没谱的符合多普勒展宽方法。由于杂质的存在，被俘获在V-I复合物中的正电子湮灭了电子。与价电子相比，与芯电子的湮灭产生更大的多普勒频移，因此可以通过分析高电子动量区域来识别杂质。CDB方法使湮没谱的峰背比提高到10^5左右，可以讨论杂质原子的芯电子引起的精细结构。本项目对不同离子注入Si中的缺陷进行了研究，首先发现Si离子注入Si的CDB谱可以作为Si中缺陷研究的参考。在CDB谱的高动量区出现了V-O、V-F和V-H络合物的特征结构。从CDB谱和正电子寿命，缺陷的行为已被考虑。例如，Si中注入O所产生的缺陷被确定为V_3O，在600°C退火时，V_3O转化为V_6O_2。800°C退火导致V_O_6的形成<10>。此外，我们还研究了Cu离子注入Fe中的缺陷。在小于5 × 10 ^ /cm ^2的注入量下，在样品的表面层中观察到简单的空位型缺陷<14>，而在5 × 10 ^ /cm ^<15>2的注入量下，已经发现空位的内壁被Cu原子覆盖。与正电子寿命测量相结合，CDB技术成为研究缺陷结构，特别是空位-杂质复合体的有力工具。