Oxygen "Getter" Effects on Microstructure and Carrier Transport in Low Temperature Combustion-Processed a-InXZnO (X = Ga, Sc, Y, La) Transistors
Oxygen "Getter" Effects on Microstructure and Carrier Transport in Low Temperature Combustion-Processed a-InXZnO (X = Ga, Sc, Y, La) Transistors
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DOI：
10.1021/ja403586x
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发表时间：
2013-07-24
影响因子：
15
通讯作者：
Marks, Tobin J.
中科院分区：
文献类型：
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作者：
Hennek, Jonathan W.;Smith, Jeremy;Marks, Tobin J.
在氧化物半导体中，例如基于氧化铟锌 (IXZO) 的半导体，强氧结合金属离子（“吸氧剂”）X 的作用是控制 O 空位并增强晶格形成，从而调节载流子浓度和传输特性。在这里，我们系统地研究了 IXZO 系列中 X = Ga3+ 与 X = Sc3+ -> Y3+ -> La3+ 的作用，它们具有相似的化学特性，但离子半径增加。 IXZO 薄膜首次通过低温燃烧合成从宽组成范围的溶液中制备。通过前体溶液的热分析、掠入射角 X 射线衍射 (GIAXRD)、原子力显微镜 (AFM)、X 射线光电子能谱 (XPS) 和具有高角度环形暗场 (HAADF) 成像的扫描透射电子显微镜 (STEM) 来表征薄膜。所有 X 均实现了优异的薄膜晶体管 (TFT) 性能，在 300 摄氏度处理后，最佳成分显示 Ga3+、Sc3+、Y3+ 和 La23+ 的电子迁移率分别为 5.4、2.6、2.4 和 1.8 cm2 V-1 s(-1)，I-on/I-off = 107-108。对 LXZO TFT 正偏压应力响应的分析表明，X = Ga3+ 的迁移率 (mu) 优于预应力值的 95% 以上，阈值电压偏移 (Delta V-T) < 1.6 V，而其他三价离子的 mu 保留率 < 85%，Delta V-T 接近 20 V。详细的微观结构分析表明，Ga3+ 最有效地促进氧化物晶格的形成。我们得出结论，金属氧化物晶格形成焓 (Delta H-L) 和金属离子半径是 IXZO 吸氧剂功效的最佳预测指标。
In oxide semiconductors, such as those based on indium zinc oxide (IXZO), a strong oxygen binding metal ion ("oxygen getter"), X, functions to control O vacancies and enhance lattice formation, hence tune carrier concentration and transport properties. Here we systematically study, in the IXZO series, the role of X = Ga3+ versus the progression X = Sc3+ -> Y3+ -> La3+, having similar chemical characteristics but increasing ionic radii. IXZO films are prepared from solution over broad composition ranges for the first time via low-temperature combustion synthesis. The films are characterized via thermal analysis of the precursor solutions, grazing incidence angle X-ray diffraction (GIAXRD), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy (STEM) with high angle annular dark field (HAADF) imaging. Excellent thin-film transistor (TFT) performance is achieved for all X, with optimal compositions after 300 degrees C processing exhibiting electron mobilities of 5.4, 2.6, 2.4, and 1.8 cm2 V-1 s(-1) for Ga3+, Sc3+, Y3+, and La23+, respectively, and with I-on/I-off = 107-108. Analysis of the LXZO TFT positive bias stress response shows X = Ga3+ to be superior with mobilities (mu) retaining >95% of the prestress values and threshold voltage shifts (Delta V-T) of < 1.6 V, versus < 85% mu retention and Delta V-T approximate to 20 V for the other trivalent ions. Detailed microstructural analysis indicates that Ga3+ most effectively promotes oxide lattice formation. We conclude that the metal oxide lattice formation enthalpy (Delta H-L) and metal ionic radius are the best predictors of IXZO oxygen getter efficacy.