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

Abstract

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 cm2/ $\text {V}\cdot \text {s}$ , 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 O2-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.