Defects in Amorphous Semiconductors: The Case of Amorphous Indium Gallium Zinc Oxide
Defects in Amorphous Semiconductors: The Case of Amorphous Indium Gallium Zinc Oxide
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DOI：
10.1103/physrevapplied.9.054039
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发表时间：
2018-05-25
影响因子：
4.6
通讯作者：
Heremans, P.
中科院分区：
文献类型：
--
作者：
de Meux, A. de Jamblinne;Pourtois, G.;Heremans, P.
在对非晶材料缺陷进行合理分类的基础上，提出了一个描述非晶铟镓锌氧化物（a-IGZO）中本征缺陷和氢杂质的简化模型。所提出的方法包括将缺陷组织成两类：点缺陷，产生结构异常，如金属-金属或氧-氧键，以及从材料化学计量的变化中出现的缺陷，如空位和间隙原子。基于第一性原理模拟，我们认为第二类缺陷总是作为完美的施主或完美的受主。这种分类简化和合理化的性质，在非晶相的缺陷。在a-IGZO中，最重要的点缺陷是金属-金属键（或小金属簇）和过氧化物（O-O单键）。电子被金属-金属键捕获并通过形成过氧化物释放。氢的存在会导致另外两种类型的缺陷：作为受体的金属-氢缺陷和作为供体的氧-氢缺陷。这些缺陷的影响与在a-IGZO中观察到的不同不稳定性有关。具体地说，氢和氧的扩散与正偏压和负偏压应力有关，而负偏压光照应力源于过氧化物的形成。
Based on a rational classification of defects in amorphous materials, we propose a simplified model to describe intrinsic defects and hydrogen impurities in amorphous indium gallium zinc oxide (a-IGZO). The proposed approach consists of organizing defects into two categories: point defects, generating structural anomalies such as metal-metal or oxygen-oxygen bonds, and defects emerging from changes in the material stoichiometry, such as vacancies and interstitial atoms. Based on first-principles simulations, it is argued that the defects originating from the second group always act as perfect donors or perfect acceptors. This classification simplifies and rationalizes the nature of defects in amorphous phases. In a-IGZO, the most important point defects are metal-metal bonds (or small metal clusters) and peroxides (O-O single bonds). Electrons are captured by metal-metal bonds and released by the formation of peroxides. The presence of hydrogen can lead to two additional types of defects: metal-hydrogen defects, acting as acceptors, and oxygen-hydrogen defects, acting as donors. The impact of these defects is linked to different instabilities observed in a-IGZO. Specifically, the diffusion of hydrogen and oxygen is connected to positive-and negative-bias stresses, while negative-bias illumination stress originates from the formation of peroxides.