IEEE Journal of the Electron Devices Society (Jan 2020)

Asymmetric Low Metal Contamination Ni-Induced Lateral Crystallization Polycrystalline-Silicon Thin-Film Transistors With Low OFF-State Currents for Back-End of Line (BEOL) Compatible Devices Applications

  • Po-Yi Kuo,
  • Shao-Chi Lo,
  • Hsiu-Hsuan Wei,
  • Po-Tsun Liu

DOI
https://doi.org/10.1109/JEDS.2020.3030962
Journal volume & issue
Vol. 8
pp. 1317 – 1322

Abstract

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In this work, polycrystalline-silicon thin-film transistors (poly-Si TFTs) with asymmetric low metal contamination Ni-induced lateral crystallization (LC-NILC) poly-Si channel and high-κ HfO2 gate insulator (GI) have been successfully fabricated and demonstrated for the first time. The amounts of Ni diffused into the poly-Si film can be effectively reduced by Ni removal processes prior to NILC. The asymmetric LC-NILC poly-Si TFTs exhibit higher field-effect mobility (μFE), steeper ideal subthreshold swing (S.S.), larger ON/OFF currents ratio (ION/IOFF), better uniformity, and improved C-V curves compared to traditional NILC (T-NILC) poly-Si TFTs owing to better crystallization quality and less low metal contamination. These remarkable device characteristics and the matched complementary TFTs (C-TFTs) electrical characteristics with low IOFF and low operation voltages make the asymmetric LCNILC poly-Si TFTs promising for the future back-end of line (BEOL) compatible devices applications in monolithic three-dimension integrated circuits (3D-ICs).

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