Abstract
We report crystallization of amorphous silicon (a-Si) thin films and improvement of thin film transistors (TFTs) characteristics using 2.45 GHz microwave heating assisted with carbon powders. Undoped 50-nm-thick a-Si films were formed on quartz substrates and heated by microwave irradiation for 2, 3, and 4 min. Raman scattering spectra revealed that the crystalline volume ratio increased to 0.42 for the 4-min heated sample. The dark and photo electrical conductivities measured by Air mass 1.5 at 100 mW/cm2 were 2.6x10-6 and 5.2x10-6 S/cm in the case of 4-min microwave heating followed by 1.3x106-Pa-H2O vapor heat treatment at 260°C for 3 h. N channel polycrystalline silicon TFTs characteristics were improved by the combination of microwave heating with high-pressure H2O vapor heat treatment. The threshold voltage decreased from 5.3 to 4.2 V and the effective carrier mobility increased from 18 to 25 cm2/Vs.
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This work was partly supported by Grant-in-Aid for Scientific Research C (#25420282 and #23560360) from the Ministry of Education, Culture, Sports, Science and Technology of Japan and Sameken Co., Ltd.
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Nakamura, T., Yoshidomi, S., Hasumi, M. et al. Crystallization of Amorphous Silicon Thin Films by Microwave Heating. MRS Online Proceedings Library 1666, 115–120 (2014). https://doi.org/10.1557/opl.2014.920
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DOI: https://doi.org/10.1557/opl.2014.920