Remarkable changes in interface O vacancy and metal-oxide bonds in amorphous indium-gallium-zinc-oxide thin-film transistors by long time annealing at 250 °C

Journal Article · Mon Dec 08 00:00:00 EST 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4903874· OSTI ID:22395505

Chowdhury, Md Delwar Hossain; Um, Jae Gwang; Jang, Jin ^[1]

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1. Advanced Display Research Center and Department of Information Display, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

We have studied the effect of long time post-fabrication annealing on negative bias illumination stress (NBIS) of amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film-transistors. Annealing for 100 h at 250 °C increased the field effect mobility from 14.7 cm{sup 2}/V s to 17.9 cm{sup 2}/V s and reduced the NBIS instability remarkably. Using X-ray photoelectron spectroscopy, the oxygen vacancy and OH were found to exist at the interfaces of a-IGZO with top and bottom SiO{sub 2}. Long time annealing helps to decrease the vacancy concentration and increase the metal-oxygen bonds at the interfaces; this leads to increase in the free carrier concentrations in a-IGZO and field-effect mobility. X-ray reflectivity measurement indicated the increment of a-IGZO film density of 5.63 g cm{sup −3} to 5.83 g cm{sup −3} (3.4% increase) by 100 h annealing at 250 °C. The increase in film density reveals the decrease of O vacancy concentration and reduction of weak metal-oxygen bonds in a-IGZO, which substantially helps to improve the NBIS stability.

• OSTI ID: 22395505
• Journal Information: Applied Physics Letters, Vol. 105, Issue 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
CARRIER MOBILITY
CONCENTRATION RATIO
FABRICATION
GALLIUM COMPOUNDS
ILLUMINANCE
INDIUM COMPOUNDS
INTERFACES
OXYGEN
REFLECTIVITY
SILICON OXIDES
STRESSES
THIN FILMS
TRANSISTORS
VACANCIES
X-RAY PHOTOELECTRON SPECTROSCOPY
ZINC OXIDES