Titanium in silicon: Lattice positions and electronic properties
Titanium in silicon: Lattice positions and electronic properties
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DOI：
10.1063/1.4871702
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发表时间：
2014-04-14
影响因子：
4
通讯作者：
Coutinho, J.
中科院分区：
文献类型：
--
作者：
Markevich, V. P.;Leonard, S.;Coutinho, J.
二次离子质谱（西姆斯）和深能级瞬态谱测量进行了直拉（Cz）和浮区生长（FZ）的硅晶体，这是注入钛离子和退火温度范围600-900 ℃。在650 ℃退火的Cz-和FZ-Si中，Ti原子的电学行为不同，尽管Ti西姆斯曲线相似。认为FZ-Si晶体中的间隙Ti原子（Ti-i）与位错诱导空位相互作用，占据替位（Ti-s）。在这项工作中或在以前的实验文献中没有检测到可以分配给Ti-s的能级。然而，先前的计算表明，Ti-s是Si中的深受主。我们表明，从密度泛函计算，适当考虑的d-壳层内的Ti杂质的电子结构的Ti-s的带隙中没有水平的相互作用。计算结果表明，Ti-i是更积极的比Ti-s和Ti-i结合更强烈的硅空位比间隙氧，解释FZ和CZ辐照材料之间观察到的差异。(C)2014 AIP Publishing LLC.
Secondary ion mass spectroscopy (SIMS) and deep level transient spectroscopy measurements were carried out on Czochralski (Cz)- and float-zone-grown (FZ) Si crystals, which were implanted with Ti ions and annealed in the temperature range 600-900 degrees C. The electrical behavior of Ti atoms is found to be different in Cz- and FZ-Si annealed at 650 degrees C, although the Ti SIMS profiles are similar. It is argued that interstitial Ti atoms (Ti-i) in FZ-Si crystals interact with implantation-induced vacancies and take a substitutional position (Ti-s). No energy levels which can be assigned to Ti-s have been detected in this work or in previous experimental literature. However, previous calculations suggest that Ti-s is a deep acceptor in Si. We show from density functional calculations that by taking proper account of interactions within the d-shell of the Ti impurity the electronic structure of Ti-s has no levels in the band gap. The calculations show that Ti-i is more energetically favorable than Ti-s and that Ti-i binds more strongly to the silicon vacancy than interstitial oxygen does, explaining the observed differences between FZ- and Cz-irradiated materials. (C) 2014 AIP Publishing LLC.