Investigation of the effects of Mg incorporation into InZnO for high-performance and high-stability solution-processed thin film transistors

Abstract

We have fabricated high-performance and high-stability sol-gel-processed MgInZnO thin films transistors with varying Mg content. As the Mg content was increased, the turn-on-voltage increased and the off-current decreased. This is because the incorporation of Mg (with low standard electrode potential and high optical band gap, Eopt, when oxidized) causes reduction in the oxygen vacancy, acting as a carrier source, and an increase in Eopt of the film. This results in reduction in carrier concentration of the film. Small grains and smooth morphology by varying the Mg content lead to an improvement of the mobility, on-current, and subthreshold gate swing.

The formation of InZnO lattices incorporating Ba for thin-film transistors using a solution process

“…Previously, our research group has reported studies on MgInZnO [4], HfInZnO [5], YInZnO [6], and LaInZnO [7] TFTs using a solution process to replace Ga in the IZO lattice. These include alkaline earth metals and transition metals, and elements in group 2 and groups 3-4 of the periodic table, respectively.…”

Control of electrical properties and gate bias stress stability in solution-processed a-IZO TFTs by Zr doping

“…Park et al reported Zr-doped IZO TFTs with excellent gate bias stability fabricated via radio frequency sputtering [22]. The standard electrode potential of Zr (À1.45) is lower than those of the other atoms composed AOS TFTs such as In (À0.34), Zn (À0.76) and Sn (À0.13) [23,24]. In addition, the band gap of ZrO 2 (~7.0 eV) is larger than In 2 O 3 (3.6 eV), ZnO (3.3 eV), SnO 2 (3.6 eV) [23,24].…”

“…The standard electrode potential of Zr (À1.45) is lower than those of the other atoms composed AOS TFTs such as In (À0.34), Zn (À0.76) and Sn (À0.13) [23,24]. In addition, the band gap of ZrO 2 (~7.0 eV) is larger than In 2 O 3 (3.6 eV), ZnO (3.3 eV), SnO 2 (3.6 eV) [23,24]. Therefore, it can be expected that the Zr addition is effective as a carrier suppressor.…”

Overview of electroceramic materials for oxide semiconductor thin film transistors

“…The researchers suggested that high postannealing (300°C) treatment of a-GaSnZnO TFTs produced better electrical performance and stability than those of a-IGZO TFTs due to the Ga 3+ and Sn 4+ ions. There have been many similar demonstrations to date involving Si, Al, Zr, Hf, Ga, and Sn with InZnO and ZnSnO matrices, aimed at improving electrical performance (e.g., μ fe and stability) [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52].…”

“…Another approach has been focused on exchanging Ga with other elements such as Zr [40], Hf [41], La [49], Mg [50], and Si [44] to form amorphous In(Zr, Hf, La, Mg, Si)ZnO-matrices since these elements can act as carrier-suppressors within InZnO as well as network stabilizers. These carriersuppressors normally have relatively high electro-negativities for binding oxygen strongly within a crystalline structure.…”