High-pressure Gas Activation for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film Transistors at 100 °C

Abstract

We investigated the use of high-pressure gases as an activation energy source for amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors (TFTs). High-pressure annealing (HPA) in nitrogen (N2) and oxygen (O2) gases was applied to activate a-IGZO TFTs at 100 °C at pressures in the range from 0.5 to 4 MPa. Activation of the a-IGZO TFTs during HPA is attributed to the effect of the high-pressure environment, so that the activation energy is supplied from the kinetic energy of the gas molecules. We reduced the activation temperature from 300 °C to 100 °C via the use of HPA. The electrical characteristics of a-IGZO TFTs annealed in O2 at 2 MPa were superior to those annealed in N2 at 4 MPa, despite the lower pressure. For O2 HPA under 2 MPa at 100 °C, the field effect mobility and the threshold voltage shift under positive bias stress were improved by 9.00 to 10.58 cm2/V.s and 3.89 to 2.64 V, respectively. This is attributed to not only the effects of the pressurizing effect but also the metal-oxide construction effect which assists to facilitate the formation of channel layer and reduces oxygen vacancies, served as electron trap sites.

The self-activated radical doping effects on the catalyzed surface of amorphous metal oxide films

“…To solve this issue, AOSs are deposited under the oxygen-rich condition in order to reduce oxygen vacancy, but it inevitably accompanies a decrease in mobility. Thus, many studies regarding the reduction of V o without mobility deterioration, such as UV annealing 12 and high pressure oxygen annealing 13 , are reported. These methods can increase the metal oxide bond and decrease V o by chemical oxidation but it requires a prolonged time (1–2 hours) and additional external energy source.…”

P‐194: Late‐News Poster: Highly Stable Thin‐Film Transistors Based on Amorphous Perovskite Semiconductors

“…Figure 2 (a) shows the bond ratio of ZTO and ZBTO films by XPS O 1s spectra. The raw O 1s peak spectra was resolved into three peaks named metal -oxygen (530.1 eV), oxygen deficient (531.2 eV) and contaminations (532.5 eV) [6]. Note that the ratio of contamination of each thin-films was skipped in fig.…”

47-3:Invited Paper: Various Low-Temperature Activation Methods for IGZO TFTs in Flexible Displays

“…We call this effect as "pressurizing effect." with annealing temperature of 100ºC [5] We have also conducted HPA activation of IGZO TFTs in O2 gas as shown in Figure 6. Surprisingly, the O2 pressure required to activate the IGZO TFTs was half that with N2 gas.…”

“…7. PBS stability test of (a) HPA-activated in N2 gas and (b) HPA-activated in O2 gas IGZO TFTs with annealing temperature of 100ºC [5]…”

“…Transfer characteristics of HPA-activated IGZO TFTs according to varying O2 pressures (0.5 to 4 MPa)with annealing temperature of 100ºC[5] …”