Solution processed lanthanum aluminate gate dielectrics for use in metal oxide-based thin film transistors

Journal Article · Mon May 18 04:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4921262· OSTI ID:22402478

Esro, M.; Mazzocco, R.; Kolosov, O.; Krier, A. ^[1]; Vourlias, G. ^[2]; Milne, W. I. ^[3]

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1. Physics Department, Lancaster University, Lancaster, LA1 4YB (United Kingdom)
2. Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
3. Department of Engineering, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

We report on ZnO-based thin-film transistors (TFTs) employing lanthanum aluminate gate dielectrics (La{sub x}Al{sub 1−x}O{sub y}) grown by spray pyrolysis in ambient atmosphere at 440 °C. The structural, electronic, optical, morphological, and electrical properties of the La{sub x}Al{sub 1−x}O{sub y} films and devices as a function of the lanthanum to aluminium atomic ratio were investigated using a wide range of characterization techniques such as UV-visible absorption spectroscopy, impedance spectroscopy, spectroscopic ellipsometry, atomic force microscopy, x-ray diffraction, and field-effect measurements. As-deposited LaAlO{sub y} dielectrics exhibit a wide band gap (∼6.18 eV), high dielectric constant (k ∼ 16), low roughness (∼1.9 nm), and very low leakage currents (<3 nA/cm{sup 2}). TFTs employing solution processed LaAlO{sub y} gate dielectrics and ZnO semiconducting channels exhibit excellent electron transport characteristics with hysteresis-free operation, low operation voltages (∼10 V), high on/off current modulation ratio of >10{sup 6}, subthreshold swing of ∼650 mV dec{sup −1}, and electron mobility of ∼12 cm{sup 2} V{sup −1} s{sup −1}.

• OSTI ID: 22402478
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 20 Vol. 106; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ABSORPTION SPECTROSCOPY
ALUMINATES
ALUMINIUM
ATOMIC FORCE MICROSCOPY
DIELECTRIC MATERIALS
ELECTRON MOBILITY
LANTHANUM COMPOUNDS
LEAKAGE CURRENT
PERMITTIVITY
PYROLYSIS
THIN FILMS
TRANSISTORS
ULTRAVIOLET SPECTRA
X-RAY DIFFRACTION
ZINC OXIDES