Investigation of Low-Frequency Noise Properties in High-Mobility ZnON Thin-Film Transistors

We investigate the low-frequency noise (LFN) properties of amorphous zinc oxynitride (a-ZnON) thin-film transistors (TFTs) exhibiting high field-effect mobilities ranging from 48.5 to 118.9 cm
²
/
$\text {V}\cdot \text {s}$
, depending on the gas flow rates during the deposition process. The measured noise power spectral density of the drain current shows that the LFN in a-ZnON TFTs obeys the classical 1/
$f$
noise theory, i.e., it is proportional to 1/
$f^{\mathrm {\gamma }}$
with
$\gamma \sim 1$
in the frequency range from 10 Hz to 1 kHz. The LFN from the a-ZnON TFT is successfully interpreted by the correlated number fluctuation-mobility fluctuation model. The near-interface dielectric trap density (
$N_{T})$
and the Coulomb scattering coefficient (
$\alpha _{S})$
extracted from the measured LFN in a-ZnON TFTs are similar to those from the previously reported values for amorphous indium–gallium–zinc oxide TFTs. The relatively large values of
$N_{T}$
and
$\alpha _{S}$
from the a-ZnON TFTs formed under O
₂
-rich environment are mainly attributed to the high degree of disorder of the a-ZnON channel layer caused by the energetically broad and high density of subgap tail states.