Current-voltage and flicker noise analysis and unified modeling for amorphous indium-gallium-zinc-oxide thin film transistors with etch stop layer from 298 to 333 K

We propose a unified DC and flicker noise model for bottom-gate amorphous InGaZO (a-IGZO) thin film transistors (TFTs) with an etch stop layer (ESL) valid for subthreshold, linear, and saturation regimes. A recent study carried out by our group about the origin of 1/f noise in four ESL a-IGZO TFTs with gate lengths 15, 20, 30, and 50 μ m and a width of 100 μ m revealed that carrier number fluctuation is the dominant mechanism of flicker noise in these specific devices and the contact resistances do not significantly contribute to the overall noise level. In this paper, we extended the work to develop a physics based 1/f noise model for ESL a-IGZo TFTs. The unified model and parameter extraction method, a technique developed for accurate parameter extraction and modeling of TFT device characteristics, is adapted to develop the I-V model. The noise model is subsequently derived taking into account the observed correlated mobility fluctuation based on the unified 1/f noise modeling idea. Results showed an excellent agreement between the experimental and modeled data for both the DC and flicker noise behavior of sample ESL a-IGZO TFTs over a broad range of bias conditions, at 298, 315, and 333 K operating temperatures.