Crystallization behavior of amorphous indium-gallium-zinc-oxide films and its effects on thin-film transistor performance
Amorphous indium-gallium-zinc oxide (a-IGZO) films were deposited by DC magnetron sputtering and post-annealed in air at 300-1000 °C for 1 h to investigate the crystallization behavior in detail. X-ray diffraction, electron beam diffraction, and high-resolution electron microscopy revealed that the...
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Published in | Japanese Journal of Applied Physics Vol. 55; no. 3; pp. 35504 - 35508 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
The Japan Society of Applied Physics
01.03.2016
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Online Access | Get full text |
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Summary: | Amorphous indium-gallium-zinc oxide (a-IGZO) films were deposited by DC magnetron sputtering and post-annealed in air at 300-1000 °C for 1 h to investigate the crystallization behavior in detail. X-ray diffraction, electron beam diffraction, and high-resolution electron microscopy revealed that the IGZO films showed an amorphous structure after post-annealing at 300 °C. At 600 °C, the films started to crystallize from the surface with c-axis preferred orientation. At 700-1000 °C, the films totally crystallized into polycrystalline structures, wherein the grains showed c-axis preferred orientation close to the surface and random orientation inside the films. The current-gate voltage (Id-Vg) characteristics of the IGZO thin-film transistor (TFT) showed that the threshold voltage (Vth) and subthreshold swing decreased markedly after the post-annealing at 300 °C. The TFT using the totally crystallized films also showed the decrease in Vth, whereas the field-effect mobility decreased considerably. |
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ISSN: | 0021-4922 1347-4065 |
DOI: | 10.7567/JJAP.55.035504 |