Formation Mechanism of Solution-Processed Nanocrystalline InGaZnO Thin Film as Active Channel Layer in Thin-Film Transistor

Abstract

Solution-processed indium gallium zinc oxide (IGZO) thin films as an active channel layer in thin-film transistors (TFTs) were successfully prepared by a spin-coating method using acetate- and nitrate-based precursors. In the range of 60–130°C , indium, gallium, and zinc precursors were dissociated and then hydrolyzed to metal hydroxides. InGanormalZn2normalO5 compound was synthesized at ∼196°C and crystallized at 305–420°C . A spin-coated IGZO film annealed at 450°C had smooth morphology and fine grains with an average size of ∼15nm . In solution-processed IGZO TFTs using nanocrystalline films prepared at 450°C , the on-to-off ratio, a field effect mobility, and the subthreshold swing voltage were ∼106 , 0.96cm2∕Vs , and 1.39V /decade, respectively.

Investigation of solution-processed amorphous SrInZnO thin film transistors

“…Because S.S is directly related to the trap density, the improvements in S.S and I on /I off can be explained by the trap density reduction in the thin film as the Sr at% increased. In our experiment, the Sr 20 at% TFT showed the best performance, and we determined that Sr acted as a carrier suppressor in the SIZO thin film as Ga does in GIZO thin films [1][2]7]. Hall measurements showed that the carrier concentration decreased from 4.739 Â 10 16 to 3.428 Â 10 13 cm À 3 and the resistivity increased from 0.45 to 1073 O cm with increased Sr, as shown in Fig.…”

“…Because of this unique carrier transport mechanism, some ZnO-based materials, including post-transition metal cations (In 3 + or Sn 4 + ) such as InZnO (IZO) [5] and ZnSnO (ZTO) [6], have been investigated. To achieve additional controllability of the thin film transistor (TFT) based on this concept, there have been numerous attempts to include a third carrier suppressor since the use of Ga was reported by Hosono et al [1][2][3][7][8][9][10][11][12]. SrO is a known electrical insulator [13][14][15][16] with a bandgap of 5.7 eV [13], an electronegativity of 0.95, and a dielectric constant of 3.2 [17].…”

Solution-processed hafnium oxide dielectric thin films for thin-film transistors applications

“…The peak around 3369 cm -1 shows the stretching vibration of O-H bounding. The asymmetric CH 3 deformation vibration (1438, 1377, and 1319 cm -1 ) and vibrations of C-H (1589, 1674 cm -1 ) were also observed in the HfO x thin films [28]. It is expected that the condensation was promoted by decomposing these organic groups.…”

Influence of thermal parameter on solution-processed Zr-doped ZTO thin-film transistors

“…broad endothermic peak was observed in the temperature ranges 190e320 C. For IGZO system, a small weight loss is associated with highly exothermic reactions such as dehydroxylation and alloy formation [20]. However, in ZZTO system, the dehydroxylation and alloy formation peaks exhibited a broad endothermic reaction.…”

“…1. Three apparent weight-loss stages could be observed in the following temperature ranges: 60e140 C, 190e320 C, and 420e550 C. The first endothermic reaction occurring at 60e140 C was accompanied by large weight loss, which could be attributed to the decomposition and hydrolysis of Zn(CH 3 COO) 2 $2H 2 O, SnCl 2 , and ZrCl 4 [20]. The evaporation of water and 2-methoxyethanol and the loss of organic components such as the ethoxy group also contributed to the weight loss observed in this temperature range.…”