Details

Autor(en) / Beteiligte

• Hennek, Jonathan W
• Smith, Jeremy
• Yan, Aiming
• Kim, Myung-Gil
• Zhao, Wei
• Dravid, Vinayak P
• Facchetti, Antonio
• Marks, Tobin J

Titel

Oxygen “Getter” Effects on Microstructure and Carrier Transport in Low Temperature Combustion-Processed a‑InXZnO (X = Ga, Sc, Y, La) Transistors

Ist Teil von

• Journal of the American Chemical Society, 2013-07, Vol.135 (29), p.10729-10741

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2013

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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 °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 La3+, respectively, and with I on/I off = 107–108. Analysis of the IXZO TFT positive bias stress response shows X = Ga3+ to be superior with mobilities (μ) retaining >95% of the prestress values and threshold voltage shifts (ΔV T) of <1.6 V, versus <85% μ retention and ΔV T ≈ 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 (ΔH L) and metal ionic radius are the best predictors of IXZO oxygen getter efficacy.