Solution processed amorphous gallium-incorporated tin oxide thin-film transistors

Abstract

In this paper, we prepared amorphous gallium-incorporated tin oxide (a-SnGaO) thin-film transistors (TFTs) with respect to various Ga contents and annealing temperatures. All TFTs exhibit excellent switching characteristics. As the gallium content increases, the off-state current of the a-SnGaO TFTs decreases, the threshold voltage (V th ) shifts towards positive voltage, and the subthreshold swing (S.S.) improves. The optimal gallium content is 20 at%, the corresponding saturation mobility of a-SnGaO TFTs is 5.2 cm 2 V −1 s −1 , the threshold voltage is −2.3 V, and the S.S. is 0.7 V dec. −1 . The switching ratio is 1.5 × 10 6 . Furthermore, we investigated the effect of annealing temperature on the electrical properties of a-SnGaO TFTs. It was found that as the annealing temperature increases, the mobility of a-SnGaO TFTs increases and the S.S. improves, which is greatly due to the increase of free electrons and reduction of defect states in the channel layer.

Compositional Engineering of Hf‐Doped InZnSnO Films for High‐Performance and Stability Amorphous Oxide Semiconductor Thin Film Transistors

“…As shown in Table S2 in the Supporting Information, the InZnSnO channel films have much larger electron concentrations (1 × 10 19 -6 × 10 19 cm −3 ) than those of other metal oxide channel layers which have been previously reported (10 15 -10 17 cm −3 ). [36,41,42] It is clear that the incorporation of Hf cations into InZnSnO matrix via combinational sputtering process reduces the electron concentration in channel films, but the electron concentration in channel layer is still high. Therefore, large amounts of electrons are trapped, and the hysteresis has existed when gate bias is applied, even after the incorporation of Hf cations.…”

“…[35] Several elements with high bonding strength with oxygen, such as, gallium (Ga), zirconium (Zr), hafnium (Hf), and yttrium (Y), are adopted in the indium oxide channel material as an oxygen binder and a stabilizer of the channel layer. [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] Although several elements have been employed as stabilizer in oxide semiconductor channel-based TFTs, investigation of the stabilizing element in oxide semiconductor is still lacking. In particular, The Hf-doped indium zinc tin oxide (Hf:InZnSnO) channel for high performance and stable transparent thin film transistors (TFTs) is developed by using a simultaneous cosputtering of InZnSnO and HfO 2 targets.…”