Highly Stable, Solution‐Processed Ga‐Doped IZTO Thin Film Transistor by Ar/O₂ Plasma Treatment

Abstract

their high optical transparency and high mobility. The undoped InO x and ZnO have a crystalline structure with high carrier concentration. [23] Therefore, many attempts are carried out to improve TFT performance by using multi-component metal-oxides. [24][25][26][27][28][29][30][31][32] IGZO is a widely used metal-oxide because of its amorphous structure and relatively high mobility. [8,32] The mixing of two or more cations with different sizes and ionic charges is tried for amorphous phase with suppressing crystallization and carrier concentration. [24] The incorporation of an appropriate quantity of cations is required to form the substitutional doping and strong chemical bonding with oxygen ions for stable oxide TFTs. [25] The ionic radius and metal-oxygen bonding strength are the most critical parameters to improve the mobility and stability of metal oxide TFTs. To enhance the bias stability of oxide TFT, carrier suppressors such as Ga 3+ , Gd 3+ , La 3+ , Sc 3+ , and Y 3+ can be used. Ga can be a good choice due to its lower ionic radius (62 pm) and relatively strong bonding strength with oxygen (353.5 kJ mol −1 ). [33] The selection of an appropriate percentage of carrier suppressor is a vital parameter to control the carrier concentration. But, excess doping can modify the material structure, which leads to deteriorating device performance. Ga is used for IGZO, indium-gallium oxide (IGO), [26] and indium-gallium-zinc-tin oxide (IGZTO), [27] so that we selected Ga doping in IZTO to improve mobility and stability. The solution-processed alloyed form of the oxide TFTs fabricated using In-Ga-O, [26] indium-zinc oxide (In-Zn-O), [28] indiumzinc-tin oxide (In-Zn-Sn-O), [29] aluminum-doped indium zinc tin oxide (Al-In-Zn-Sn-O), [30] zinc tin oxide (Zn-Sn-O), [31] and indium gallium zinc oxide (In-Ga-Zn-O) [32] as an active channel material have been widely studied for the high performance of the solution based oxide TFTs. To increase mobility, various treatments were carried out such as heat-treatment [34] and plasma-treatment. [35][36][37] In this study, we report the Ar/O2 plasma treatment effect on the performance of Ga-doped IZTO TFT. First, we improve the performance of the a-IZTO TFT by varying the Ga doping ratio from 0 to 20%. It is found that 10% Ga-doped IZTO shows the best performance. To further improve the TFT performance, the Ar/O 2 plasma treatment was carried out. The carbon concentration at the surface of Ga-doped IZTO could be reduced by Ar/O 2 plasma treatment, which is confirmed from the XPS The effects of gallium doping into indium-zinc-tin oxide (IZTO) thin film transistors (TFTs) and Ar/O 2 plasma treatment on the performance of a-IZTO TFT are reported. The Ga doping ratio is varied from 0 to 20%, and it is found that 10% gallium doping in a-IZTO TFT results in a saturation mobility (µs at ) of 11.80 cm 2 V −1 s −1 , a threshold voltage (V th ) of 0.17 V, subthreshold swing (SS) of 94 mV dec −1 , and on/off current ratio (I on /I off ) of 1.21 × 10 7 . Additionally, the performance of 10% G...

Remarkable Stability Improvement of ZnO TFT with Al2O3 Gate Insulator by Yttrium Passivation with Spray Pyrolysis

“…Small ∆V TH indicates fewer defects at the interface of the GI and the active layer. The negligible change in the SS after bias stress from 0 to 1 h indicates very small trapping sites at the interface [ 32 , 33 ].…”

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

“…Since Hosono's group proposed amorphous oxide semiconductors (AOS) like amorphous IGZO channel in 2004, various metal oxide semiconductor channels including indium zinc oxide (IZO), zinc tin oxide (ZTO), gallium tin oxide (GTO), indium zinc tin oxide (IZTO), zinc oxide (ZnO), and titanium oxide (TiO 2 ) have been reported as a promising channel material for TFTs to substitute Si channel. [1][2][3][4][5][6][7][8][9][10][11][12] Many groups have extensively investigated metal oxide channel materials for thin film transistors (TFTs) for the next generation flat panel displays. Due to the large band gap and high transmittance of typical AOSs, those oxide semiconductor channels could also previous reports have covered the effects of incorporation of stabilizing dopants on the device performance and stabilities.…”

Gel-based precursors for the high-performance of n-channel GaInSnZnO and p-channel CuGaSnSO thin-film transistors

“…To improve the TFT performance, multi-component oxide semiconductors are of increasing interest, such as zirconium-indium-zinc oxide (ZIZO), aluminum-zinc-tin oxide (AZTO), amorphous indiumgallium-zinc oxide (a-IGZO), amorphous indium-zinc-tin oxide (a-IZTO), amorphous aluminum-indium-zinc-tin oxide (a-AIZTO), amorphous gallium-indium-zinc-tin oxide (a-GIZTO), yttrium-indium-zinc-tin oxide (YIZTO), lithium-indiumzinc-tin oxide (LIZTO), and magnesium-indium-zinc-tin oxide (MIZTO). [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The most attractive application of MO TFTs is active-matrix backplanes for organic light-emitting diode (OLED) display due to their high mobility, high transparency in the visible region, and low-cost production with solution process. 17,18 A vacuum process, such as sputtering, plasmaenhanced chemical vapor deposition, and atomic layer deposition, needs high manufacturing cost for display application.…”

“…[40][41][42][43][44] In a previous report, Gadoped IZTO TFT (350 C) using AlO x as a gate insulator exhibits the mobility of 11.80 cm 2 V À1 s À1 (V DS ¼ 0.1 V, and V GS ¼ 3 V). 10 H. Yang et al reported that Ga-doped ITZO TFT (350 C) exhibits mobility higher than 30 cm 2 V À1 s À1 (V DS ¼ 40 V, and V GS ¼ 20 V). Nomura et al reported the percolation conduction mechanism in multicomponent MO with heavy transition metal cations with (n À 1)d 10 ns 0 (n $ 5) electronic conguration.…”