Effects of channel dimensions on performance of a-InGaZnO4 thin-film transistors

Abstract

The authors report an investigation of the effects of channel dimensions on the properties of amorphous-InGaZnO4 (a-IGZO) thin-film transistors (TFTs) that are associated with surface depletion and surface/volume ratio. As the channel width decreased below a critical value of around 100 nm, the on current abruptly decreased and the threshold voltage abruptly increased. The magnitude of hysteresis behavior also depended on the channel size. Both of these effects result from the change of channel resistance that can be explained by surface changes due to adsorption of oxygen or water vapor. The authors also investigated short channel a-IGZO TFTs and observed short channel effects below a critical value of channel length of 900 nm. The breakdown electric field of a-IGZO was found to be in the range of 0.4–0.8 MV/cm.

Basic analog circuits with a-GIZO thin-film transistors: Modeling and simulation

“…A few papers have reported the development of physical models for a-GIZO TFTs [4], [5]. But many physical properties of the device, such as short channel and narrow width effects, still need to be properly characterized and modeled [6]. Moreover, physical models are complex and time consuming to realize.…”

Band offsets in HfO2/InGaZnO4 heterojunctions

“…Numerous groups have exploited these properties in demonstrating IGZO TFTs on unconventional substrates. [1][2][3][4][5][6][7][8][9] These types of a-IGZO TFTs have potential applications as switches in the active-matrix and driver-integrated circuits of low cost flexible displays. In order to achieve a-IGZO TFTs with high performance, it is necessary to find compatible gate dielectric materials which can provide a low trap density at the oxidegate dielectric interface and reduced operating voltage.…”

Oxide-Semiconductor-Based TFTs for Displays and Flexible Electronics

“…The as-fabricated type-II device showed hardly hysteresis in the transfer characteristics, yet under storage in the ambient condition, significant hysteresis was observed (with the shift increasing with the storage time). The larger hysteresis with longer storage in the air implies that such phenomenon is associated with the interaction of the device with gas molecules in the air (42,43). It had been reported previously that for the unpassivated or not effectively passivated oxide TFTs, water molecules in the air could interact with the oxide semiconductor (e.g., adsorption, creation of surface/interface charges etc.…”