Influence of the Amorphous Silicon Thickness on Top Gate Thin-Film Transistor Electrical Performances

Abstract

We have analyzed the influence of the hydrogenated amorphous silicon (a-Si:H) thickness on the electrical performances of top gate thin-film transistors (TFTs). We have observed that, when the a-Si:H thickness increases, the threshold voltage and the subthreshold slope decrease. The modification of the TFT apparent field-effect mobility has also been investigated: we have shown that it first increases with the a-Si:H thickness, and then decreases for thicker a-Si:H films. This change of electrical performances is most likely associated with both the variation of a-Si:H microstructure during the film depositions and the effect of parasitic source and drain series resistances. We have demonstrated that for a given TFT geometry, it is therefore possible to define an optimum a-Si:H thickness ensuring maximum TFT electrical performances, and that this optimum thickness increases significantly with the TFT channel length.

Influence of the semiconductor thickness on the electrical properties of transparent TFTs based on indium zinc oxide

“…Besides that, the increase of V T can be attributed to an higher influence of the back surface (the opposite surface to the one that is in contact with the dielectric) as d s decreases, since the surface states also present in that surface, due to their lower energies than the conduction band edge, can act as preferential traps for electrons, which would otherwise be available to form the conductive channel [11]. Similar results were observed for a-Si:H TFTs [12].…”

Gallium–Indium–Zinc-Oxide-Based Thin-Film Transistors: Influence of the Source/Drain Material

“…To evaluate the performance of different materials, the contact resistance and intrinsic semiconductor parameters were studied. For a low V DS , the total TFT-ON resistance R T can be written as [20] …”

Gate-planarized organic polymer thin film transistors

“…10 The measurement methods used to evaluate the OP-TFT electrical performance are similar to the ones developed for hydrogenated amorphous silicon (a-Si:H) TFTs in our laboratory. 11 We used a Karl Suss PM8 probe station, HP 4156A semiconductor parameter analyzer, and Interactive Characterization Software (ICS, Metrics Technology Inc, Albuquerque, NM). The device electrical characteristics presented in this paper were measured in air, at room temperature, and in the dark.…”