Open AccessEffects of low‐temperature thermal annealing on interface characteristics in IZO/IGZO dual‐channel thin‐film transistors
Author(s) -
Choi H.S.
Publication year - 2020
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
ISSN - 1350-911X
DOI - 10.1049/el.2020.1747
Subject(s) - materials science , annealing (glass) , thin film transistor , threshold voltage , optoelectronics , subthreshold slope , thermal stability , transistor , voltage , electrical engineering , composite material , layer (electronics) , physics , quantum mechanics , engineering
Dual‐channel thin‐film transistors (TFTs) show excellent effective mobility ( μ eff ) and reliability, including negative‐bias‐illumination stability. To enhance the performance of these devices, post‐thermal annealing in air is performed for 2 h at the low temperature of 250°C. To investigate the effects of low‐temperature thermal annealing, indium–zinc‐oxide/gallium–indium–zinc‐oxide (IZO/IGZO) dual‐channel TFTs with various IZO thicknesses are fabricated and examined. The observed parameters are μ eff , saturation mobility ( μ sat ), subthreshold slope (SS), and threshold voltage ( V TH ). The interface quality may be improved by low‐temperature thermal annealing, which was confirmed by the improvement in μ eff and SS . However, these performance enhancements are intensively observed only in the channels with an IZO thickness below 10 nm. When the IZO thickness becomes 10 nm or more, the improvement in μ eff due to low‐temperature thermal annealing hardly occurs. This is because μ eff is greatly influenced by the interface quality due to Coulomb scattering when the IZO thickness is <10 nm. However, for an IZO thickness above 10 nm, as phonon scattering also has a significant effect on μ eff , the improvement in interface quality by thermal annealing is small. This is also supported by low‐frequency noise measurements, which are sensitive to interface quality.