Effect of aluminum capping layer thickness on scattering mechanisms in a-IGTO thin-film transistors

초록

We studied the transport properties of amorphous In-Ga-Sn oxide (a-IGTO) thin-film transistors (TFTs) as a function of aluminum (Al) capping layer of varying thickness. Hall measurements were conducted on Hall bar devices to accurately evaluate carrier mobility and carrier concentration, excluding the influence from the contact resistance. The results revealed increased carrier mobility and carrier concentration with the Al capping layer devices. In addition, a power-law dependency between Hall mobility and sheet carrier concentration (μHall ∝ nsheet0.5) was observed for all devices, independent of Al capping-layer thickness. These results indicate that the dominant scattering mechanism most likely arises from uniform background charges within the bulk IGTO material, rather than from interface conditions.

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