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Drain-induced barrier lowering (DIBL) is one of the most critical obstacles degrading the reliability of integrated circuits based on miniaturized transistors. Here, the effect of a crystallographic structure change in InGaO [indium gallium oxide (IGO)] thin-films on the DIBL was investigated. Preferentially oriented IGO (po-IGO) thin-film transistors (TFTs) have outstanding device performances with a field-effect mobility of 81.9 ± 1.3 cm 2 /(V s), a threshold voltage ( V TH ) of 0.07 ± 0.03 V, a subthreshold swing of 127 ± 2.0 mV/dec, and a current modulation ratio of (2.9 ± 0.2) × 10 11 . They also exhibit highly reliable electrical characteristics with a negligible V TH shift of +0.09 (-0.14) V under +2 (-2) MV/cm and 60 °C for 3600 s. More importantly, they reveal strong immunity to the DIBL of 17.5 ± 1.2 mV/V, while random polycrystalline In 2 O 3 (rp-In 2 O 3 ) and IGO (rp-IGO) TFTs show DIBL values of 197 ± 5.3 and 46.4 ± 1.2 mV/V, respectively. This is quite interesting because the rp- and po-IGO thin-films have the same cation composition ratio (In/Ga = 8:2). Given that the lateral diffusion of oxygen vacancies from the source/drain junction to the channel region via grain boundaries can reduce the effective length ( L eff ) of the oxide channel, this improved immunity could be attributed to suppressed lateral diffusion by preferential growth. In practice, the po-IGO TFTs have a longer L eff than the rp-In 2 O 3 and -IGO TFTs even with the same patterned length. The effect of the crystallographic-structure-dependent L eff variation on the DIBL was corroborated by technological computer-aided design simulation. This work suggests that the atomic-layer-deposited po-IGO thin-film can be a promising candidate for next-generation electronic devices composed of the miniaturized oxide transistors.

Indium oxide (In 2 O 3 ) is a transparent wide-bandgap semiconductor suitable for use in the back-end-of-line-compatible channel layers of heterogeneous monolithic three-dimensional (M3D) devices. The structural, chemical, and electrical properties of In 2 O 3 films deposited by plasma-enhanced atomic layer deposition (PEALD) were examined using two different liquid-based precursors: (3-(dimethylamino)propyl)-dimethyl indium (DADI) and ( N , N -dimethylbutylamine)trimethylindium (DATI). DATI-derived In 2 O 3 films had higher growth per cycle (GPC), superior crystallinity, and low defect density compared with DADI-derived In 2 O 3 films. Density functional theory calculations revealed that the structure of DATI can exhibit less steric hindrance compared with that of DADI, explaining the superior physical and electrical properties of the DATI-derived In 2 O 3 film. DATI-derived In 2 O 3 field-effect transistors (FETs) exhibited unprecedented performance, showcasing a high field-effect mobility of 115.8 cm 2 /(V s), a threshold voltage of -0.12 V, and a low subthreshold gate swing value of <70 mV/decade. These results were achieved by employing a 10-nm-thick HfO 2 gate dielectric layer with an effective oxide thickness of 3.9 nm. Both DADI and DATI-derived In 2 O 3 FET devices exhibited remarkable stability under bias stress conditions due to a high-quality In 2 O 3 channel layer, good gate dielectric/channel interface matching, and a suitable passivation layer. These findings underscore the potential of ALD In 2 O 3 films as promising materials for upper-layer channels in the next generation of M3D devices.

An atomic-layer-deposited oxide nanolaminate (NL) structure with 3 dyads where a single dyad consists of a 2-nm-thick confinement layer (CL) (In 0.84 Ga 0.16 O or In 0.75 Zn 0.25 O), and a barrier layer (BL) (Ga 2 O 3 ) was designed to obtain superior electrical performance in thin-film transistors (TFTs). Within the oxide NL structure, multiple-channel formation was demonstrated by a pile-up of free charge carriers near CL/BL heterointerfaces in the form of the so-called quasi-two-dimensional electron gas (q2DEG), which leads to an outstanding carrier mobility (μ FE ) with band-like transport, steep gate swing ( SS ), and positive threshold voltage ( V TH ) behavior. Furthermore, reduced trap densities in oxide NL compared to those of conventional oxide single-layer TFTs ensures excellent stabilities. The optimized device with the In 0.75 Zn 0.25 O/Ga 2 O 3 NL TFT showed remarkable electrical performance: μ FE of 77.1 ± 0.67 cm 2 /(V s), V TH of 0.70 ± 0.25 V, SS of 100 ± 10 mV/dec, and I ON/OFF of 8.9 × 10 9 with a low operation voltage range of ≤2 V and excellent stabilities (Δ V TH of +0.27, -0.55, and +0.04 V for PBTS, NBIS, and CCS, respectively). Based on in-depth analyses, the enhanced electrical performance is attributed to the presence of q2DEG formed at carefully engineered CL/BL heterointerfaces. Technological computer-aided design (TCAD) simulation was performed theoretically to confirm the formation of multiple channels in an oxide NL structure where the formation of a q2DEG was verified in the vicinity of CL/BL heterointerfaces. These results clearly demonstrate that introducing a heterojunction or NL structure concept into this atomic layer deposition (ALD)-derived oxide semiconductor system is a very effective strategy to boost the carrier-transporting properties and improve the photobias stability in the resulting TFTs.

In this paper, the feasibility of an indium-gallium oxide (In 2(1-x) Ga 2 x O y ) film through combinatorial atomic layer deposition (ALD) as an alternative channel material for back-end-of-line (BEOL) compatible transistor applications is studied. The microstructure of random polycrystalline In 2 O y with a bixbyite structure was converted to the amorphous phase of In 2(1- x ) Ga 2 x O y film under thermal annealing at 400 °C when the fraction of Ga is ≥29 at. %. In contrast, the enhancement in the orientation of the (222) face and subsequent grain size was observed for the In 1.60 Ga 0.40 O y film with the intermediate Ga fraction of 20 at. %. The suitability as a channel layer was tested on the 10-nm-thick HfO 2 gate oxide where the natural length was designed to meet the requirement of short channel devices with a smaller gate length (<100 nm). The In 1.60 Ga 0.40 O y thin-film transistors (TFTs) exhibited the high field-effect mobility (μ FE ) of 71.27 ± 0.98 cm 2 /(V s), low subthreshold gate swing (SS) of 74.4 mV/decade, threshold voltage ( V TH ) of -0.3 V, and I ON/OFF ratio of >10 8 , which would be applicable to the logic devices such as peripheral circuit of heterogeneous DRAM. The in-depth origin for this promising performance was discussed in detail, based on physical, optical, and chemical analysis.

Ultraviolet to infrared broadband spectral detection capability is a technological challenge for sensing materials being developed for high-performance photodetection. In this work, we stacked 9 nm-thick tellurium oxide (TeO x ) and 8 nm-thick InGaSnO (IGTO) into a heterostructure at a low temperature of 150 °C. The superior photoelectric characteristics we achieved benefit from the intrinsic optical absorption range (300-1500 nm) of the hexagonal tellurium (Te) phase in the TeO x film, and photoinduced electrons are driven effectively by band alignment at the TeO x /IGTO interface under illumination. A photosensor based on our optimized heterostructure exhibited a remarkable detectivity of 1.6 × 10 13 Jones, a responsivity of 84 A/W, and a photosensitivity of 1 × 10 5 , along with an external quantum efficiency of 222% upon illumination by blue light (450 nm). Simultaneously, modest detection properties (responsivity: ∼31 A/W, detectivity: ∼6 × 10 11 Jones) for infrared irradiation at 970 nm demonstrate that this heterostructure can be employed as a broadband phototransistor. Furthermore, its low-temperature processability suggests that our proposed concept might be used to design array optoelectronic devices for wide band detection with high sensitivity, flexibility, and stability.

This paper reports the fabrication of indium gallium tin oxide (IGTO) thin-film transistors (TFTs) with ultraviolet (UV)-treated PVP- co-PMMA-based hybrid gate insulators at an extremely low temperature (≤150 °C). Synergetic hafnia loading and UV treatment were used to tailor the mechanical softness and hydroxyl fraction in the polymer dielectric film. The UV-treated hybrid dielectric film had a low hydroxyl concentration, a smoother surface, and a denser packing nature, which can be explained by the high ionicity of hafnium oxide and photon-assisted improvement in the cohesion between organic and inorganic materials. Suitability of the UV-treated hybrid dielectric film as a gate insulator was evaluated by fabricating bottom gate TFTs with sputtered IGTO films as a channel layer, which showed high carrier mobility at a low temperature. The resulting IGTO TFTs with a UV-treated hybrid gate insulator exhibited a remarkable high field-effect mobility of 25.9 cm 2 /(V s), a threshold voltage of -0.2 V, a subthreshold gate swing of 0.4 V/decade, and an I ON/OFF ratio of >10 7 even at a low annealing temperature of 150 °C. The fabricated IGTO TFTs with the UV-treated hybrid dielectric film on the plastic substrate were shown to withstand the 100 times mechanical bending stress even under an extremely small curvature radius of 1 mm due to the intrinsic stretchability of the hybrid dielectric film.