Study on interface characteristics in amorphous indium–gallium–zinc oxide thin-film transistors by using low-frequency noise and temperature dependent mobility measurements

• Temperature dependent mobility and low-frequency noise of a-IGZO TFTs are studied.
• The dominant scattering mechanism of channel carriers is found Coulomb scattering.
• The border trap density and the distribution of filled interface traps are deduced.
• Annealing at higher temperature is found effective to reduce border trap density.

In this work, the interface properties of amorphous indium–gallium–zinc oxide thin film transistors annealed at different temperatures ranging from 150 to 250 °C are studied by temperature dependent mobility and low-frequency noise (LFN) characterizations. The dominant scattering mechanism for carrier transport is found to be Coulomb scattering based on gate bias and temperature dependent mobility measurement. Meanwhile, as the annealing temperature increases, the dominant mechanism of LFN within the device channel varies from carrier number fluctuation to carrier mobility fluctuation. The border trap density as well as the distribution properties of charged border traps is deduced. The present results suggest that annealing at higher temperature has a more remarkable effect on removing deeper border traps than traps closer to the channel/dielectric interface.