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Studies of high-temperature point defects and development of crystal growth method free of secondary defects in Si with the use of hydrogen

硅高温点缺陷研究及氢无二次缺陷晶体生长方法的开发

基本信息

批准号：
11450001
负责人：
SUEZAWA Masashi
金额：
$ 2.05万
依托单位：
TOHOKU UNIVERSITY
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

项目摘要

We measured optical absorption spectra after 3-MeV electron-irradiation of hydrogenated Czochralskigrown Si crystals (abbreviated Cz.Si hereafter) at Rt. We observed optical absorption peaks due to various complexes of point defects and impurities. We first describe the result of vacancy-oxygen (VO) pair. The concentration of VO pair was proportional to the 3/4 power of electron dose, contrary to our intuition, i.e., 1. We have not yet succeeded to explain it. The pair formation rate was proportional to the 1/5 power of oxygen concentration. This weak dependence is explained by long diffusion distance of vacancy before captured by oxygen, which is due to high diffusion rate of vacancy and weak interaction between oxygen and vacancy. Contrary to the case of floating-zone grown Si crystals (FZ.Si), vacancyhydrogen complexes were not generated. This is due to VO pair formation because of high concentration of oxygen (about two orders of magnitude larger than that of hydrogen) in Cz.Si. Concentrations of self-interstitial-hydrogen complexes were larger in Cz.Si than in FZ.Si. This is due to lower rate of pair annihilation of vacancy and self-interstitial because vacancies in Cz.Si quickly form pairs with oxygen. We identified defects responsible for peaks at 1870 and 2072 cm^<-1> to be I_2H_2 and V_2H_2, respectively, based on the dendences of peak intensities on dopants and irradiation dose.We also studied the thermal stability of complexes. VO pairs decreased above 100℃ and, simultaneously, two new peaks at 2126 and 2152 cm^<-1> appeared. These two peaks are due to VOH_2 complex since 2122 and 2145 cm^<-1> peaks are due to VH_2 complex.

我们测量了3 MeV电子辐照氢化直拉法生长的Si晶体（以下简称Cz.Si）后的室温光吸收谱，观察到了由点缺陷和杂质的各种复合物引起的光吸收峰。我们首先描述了空位-氧（VO）对的结果。VO对的浓度与电子剂量的3/4次方成正比，与我们的直觉相反，即，1.电子对的形成速率与氧浓度的1/5次方成正比。这种弱的依赖性是由于空位在被氧捕获之前的扩散距离较长，这是由于空位的扩散速率较高以及氧与空位之间的相互作用较弱。相反的情况下，浮区生长的硅晶体（FZ.Si），vacancyhydrogen络合物没有产生。这是由于在Cz·Si中氧的浓度高（比氢的浓度大2个数量级左右）而形成VO对。Cz.Si中自间隙氢复合物的浓度大于FZ. Si中。这是由于空位和自填隙的对湮灭速率较低，因为Cz.Si中的空位迅速与氧形成对。根据1870和2072 cm ~ 2处的<-1>峰强度随掺杂剂和辐照剂量的变化关系，确定了相应的缺陷分别为I_2H_2和V_2H_2，并研究了配合物的热稳定性。在100℃以上，VO对减少，同时在2126和2152 cm ↑ [2]处出现两个新峰<-1>。这两个峰是由于VOH_2络合物，因为2122和2145 cm-<-1>2峰是由于VH_2络合物。