Oxygen 鈥淕etter鈥?Effects on Microstructure and Carrier Transport in Low Temperature Combustion-Processed a-InXZnO (X = Ga, Sc, Y, La) Transistors

详细信息    查看全文

• 作者：Jonathan W. Hennek ; Jeremy Smith ; Aiming Yan ; Myung-Gil Kim ; Wei Zhao ; Vinayak P. Dravid ; Antonio Facchetti ; Tobin J. Marks
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：July 24, 2013
• 年：2013
• 卷：135
• 期：29
• 页码：10729-10741
• 全文大小：724K
• 年卷期：v.135,no.29(July 24, 2013)
• ISSN：1520-5126

文摘

In oxide semiconductors, such as those based on indium zinc oxide (IXZO), a strong oxygen binding metal ion (鈥渙xygen getter鈥?, 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⁺ 鈫?Y³⁺ 鈫?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 掳C processing exhibiting electron mobilities of 5.4, 2.6, 2.4, and 1.8 cm² V^鈥? s^鈥? for Ga³⁺, Sc³⁺, Y³⁺, and La³⁺, respectively, and with I_on/I_off = 10⁷鈥?0⁸. Analysis of the IXZO TFT positive bias stress response shows X = Ga³⁺ to be superior with mobilities (渭) retaining >95% of the prestress values and threshold voltage shifts (螖V_T) of <1.6 V, versus <85% 渭 retention and 螖V_T 鈮?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 (螖H_L) and metal ionic radius are the best predictors of IXZO oxygen getter efficacy.