Novel ZrInZnO Thin‐film Transistor with Excellent Stability

Abstract

Nowadays, active-matrix organic light-emitting diode (AMOLED) technology has been intensively utilized in commercial large-size flat panel markets such as notebooks, personal computers, display monitors, and high-definition televisions. [1,2] This widespread use is due to the many attractive features that are offered by AMOLEDs, including wide viewing angles, high contrast ratios, low power consumption, and fast response times. Despite these advantages, one of the most critical issues for the technology is the inability to incorporate thin-film transistors (TFTs) in these large-sized applications (!7th generation glass size of 1.9 m  2.2 m (max)). The only mature technology compatible with producing large-sized panels (!7th generation) is based on amorphous Si (a-Si) TFTs, whose inferior long-term stability [3][4][5][6] under gate or/and drain bias stressed conditions hinders their utilization in AMOLED panels.Recently, ZnO-based TFTs have become attractive for use as driving devices in large-sized AMOLED applications, due to their better device performance and reliability; in addition, they offer large-size scalability features with good uniformity, and low product cost, comparable to their a-Si TFT counterparts. [7,8] Furthermore, the transparency of ZnO-based oxide semiconductor and their low-temperature process capability could open the opportunity to the next generation of applications, including ''see-through'' and/or ''flexible'' AMOLED displays, which cannot be realized via silicon-based TFT technologies due to their intrinsic limitations.There have been many reports of high-performance TFTs with oxide semiconductors, including ZnO, [8][9][10] InZnO, [11][12][13] ZnSnO, [14] and InGaZnO [15][16][17][18][19] as the channel materials. The field-effect mobilities (m FE ), sub-threshold gate swing (S), and I on/ off ratios of ZnO-based TFTs have been dramatically improved since Hosono and coworkers reported the usage of amorphous InGaZnO as a channel material using physical-vapor-deposition techniques.[7] Thus, the device performance of ZnO-based TFTs reported in the literature includes high mobility (>10 cm 2 V s À1 ), excellent sub-threshold gate-voltage swing (<0.4 V decade À1 ), and high I on/off ratios (>10 7 ), which are superior to those found in a-Si TFT applications. [7,8,15,16,18,19] However, the stability of ZnO-based TFT devices has remained the most important and critical issue still to be resolved to allow them to be used as driving devices in AMOLED displays. This is because any positive shift in the threshold voltage (V th ) of the driving transistor during the on-state bias stressed condition causes a rapid drop in the output drain current, leading to reduction in the luminance of the OLED device. The nonuniformity in the V th shift of the pixel driving transistors as a result of the different data voltages obviously causes the well-known problem of the image sticking in the resulting panel brightness. [20][21][22] Several studies on bias-induced instabilities in ZnO-based TFTs have reported...

High performance In2O3 thin film transistors using chemically derived aluminum oxide dielectric

“…Oxide semiconductor based TFTs have been proven to be the alternative candidates to the low mobility siliconbased TFTs, which are currently being used for display applications. 1 High performance oxide TFTs have been reported using vacuum deposition techniques [2][3][4][5] and have also been used for the demonstration of display devices. 6,7 Solution deposition techniques have also been employed for the fabrication of oxide TFTs.…”

Overview of electroceramic materials for oxide semiconductor thin film transistors

“…Indeed, various multi-component, oxide semiconductors are being examined with the aim of improving the stability of devices by proper selection of carrier-suppressors. Park et al [40], for example, reported the performance of a ZrInZnOsemiconductor device with its characteristics shown in Fig. 4(a) and (b) including a comparison with that of a-IGZO TFTs.…”

“…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.…”

Improvement on the Stability of Amorphous Indium Gallium Zinc Oxide Thin Film Transistors Using Amorphous Oxide Multilayer Source/Drain Electrodes

“…They were regarded as transparent TFTs (TTFTs) since they also have high transparency in a visible range [1][2][3], Amorphous InGaZnO (a-IGZO) was regarded as a channel layer of TTFT due its good performance, transparency, and stability [4]. There are many studies of channel layer as well as source and drain (S/D) electrodes of TTFTs, because the S/D electrodes have an effect on the electrical performance and transparency of TTFTs.…”