Improvement in the negative bias temperature stability of ZnO based thin film transistors by Hf and Sn doping

Kim, Woong-Sun; Moon, Yeon-Keon; Kim, Kyung‐Taek; Shin, Sae-Young; Ahn, Byung Du; Lee, Je‐Hun; Park, Jong-Wan

doi:10.1016/j.tsf.2011.01.402

Cited by 19 publications

(9 citation statements)

References 21 publications

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“…In addition, the field-effect mobility also decreased from 11.3 to 9.4 cm 2 /Vs, and V on increased from 0 to 0.2 V by the Hf doping. These values for HZO-TFT are comparable to or even exceed the values reported by other HZO-TFTs [12, 21, 24] and much better than those fabricated by ALD [12]. In general, oxide semiconductors containing heavy metal cations with ( n − 1) d 10 ns 0 ( n ≥ 4) electronic configurations show high electron mobility as the ns 0 orbitals are overlapped with each other.…”

Section: Resultssupporting

confidence: 76%

The Influence of Hafnium Doping on Density of States in Zinc Oxide Thin-Film Transistors Deposited via Atomic Layer Deposition

et al. 2017

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Thin-film transistors (TFTs) with atomic layer deposition (ALD) HfZnO (HZO) as channel layer and Al2O3 as gate insulator were successfully fabricated. Compared with ZnO-TFT, the stability of HZO-TFT was obviously improved as Hf doping can suppress the generation of oxygen related defects. The transfer characteristics of TFTs at different temperatures were also investigated, and temperature stability enhancement was observed for the TFT with Hf doping. The density of states (DOS) was calculated based on the experimentally obtained E a, which can explain the experimental observation. A high-field effect mobility of 9.4 cm2/Vs, a suitable turn-on voltage of 0.26 V, a high on/off ratio of over 107 and a steep sub-threshold swing of 0.3 V/decade were obtained in HZO-TFT. The results showed that temperature stability enhancement in HfZnO thin-film transistors are attributed to the smaller DOS.

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Section: Resultssupporting

confidence: 76%

The Influence of Hafnium Doping on Density of States in Zinc Oxide Thin-Film Transistors Deposited via Atomic Layer Deposition

et al. 2017

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“…Park et al [ 21 ] reported solution-processed TFTs with an alkali metal doped ZnO active layer, but the ZnO surface was sensitive to the atmosphere and the device stability was poor. Kim et al [ 22 ] reported TFTs with an Hf doped ZnO active layer, but the electrical performance was poor with a large subthreshold swing ( SS ) of 1.09 V/decade and a turn-on voltage ( V on ) of −7 V. Jiang et al [ 23 ] reported TFTs with an Al doped ZnO active layer, but the mobility was only 0.17 cm 2 ·V −1 ·s −1 . It seems difficult to attain high-performance TFTs with a ZnO based active layer without the Indium element.…”

Section: Introductionmentioning

confidence: 99%

Room-Temperature Fabricated Thin-Film Transistors Based on Compounds with Lanthanum and Main Family Element Boron

Xiao

Huang

Dong³

et al. 2018

Molecules

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For the first time, compounds with lanthanum from the main family element Boron (LaBx) were investigated as an active layer for thin-film transistors (TFTs). Detailed studies showed that the room-temperature fabricated LaBx thin film was in the crystalline state with a relatively narrow optical band gap of 2.28 eV. The atom ration of La/B was related to the working pressure during the sputtering process and the atom ration of La/B increased with the increase of the working pressure, which will result in the freer electrons in the LaBx thin film. LaBx-TFT without any intentionally annealing steps exhibited a saturation mobility of 0.44 cm2·V−1·s−1, which is a subthreshold swing (SS) of 0.26 V/decade and a Ion/Ioff ratio larger than 104. The room-temperature process is attractive for its compatibility with almost all kinds of flexible substrates and the LaBx semiconductor may be a new choice for the channel materials in TFTs.

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“…So far, several studies on bias-induced instabilities in ZnObased TFTs have reported deterioration in their electrical characteristics, 6,7 and some methods have been used to suppress the bias-induced instability, e.g., Hf, Sn, and Al dopings, annealing treatment in nitrogen ambient. 8,9 Moreover, several mechanisms have been proposed to explain the bias-induced instability, such as charge trapping or defect-state creation in the gate dielectric or at the gate dielectric/channel interface. However, since these mechanisms were developed only from the output and transfer characteristics of ZnO-based TFTs, 10,11 there are not enough experimental results to support these deductions.…”

Section: Introductionmentioning

confidence: 99%

Negative gate-bias instability of ZnO thin-film transistors studied by current–voltage and capacitance–voltage analyses

Liu

Yao

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Effects of negative gate-bias stress on the electrical properties of ZnO thin-film transistors (TFTs) are investigated. Under negative gate-bias stress, the ZnO TFTs exhibit higher carrier mobility, larger OFF-state current, and a negative shift in threshold voltage with no significant change in subthreshold slope. The time dependence of threshold-voltage shift on various bias stress conditions can be described by a logarithmic equation. Based on the analysis of hysteresis behaviors in current-voltage and capacitance-voltage characteristics before and after the negative gate-bias stress, it can be clarified that the threshold-voltage shift is predominantly attributed to the trapping of positive charge carriers in the defect states at the gate-dielectric/channel interface or in the dielectric during the negative gate-bias stress. V

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Improvement in the negative bias temperature stability of ZnO based thin film transistors by Hf and Sn doping

Cited by 19 publications

References 21 publications

The Influence of Hafnium Doping on Density of States in Zinc Oxide Thin-Film Transistors Deposited via Atomic Layer Deposition

The Influence of Hafnium Doping on Density of States in Zinc Oxide Thin-Film Transistors Deposited via Atomic Layer Deposition

Room-Temperature Fabricated Thin-Film Transistors Based on Compounds with Lanthanum and Main Family Element Boron

Negative gate-bias instability of ZnO thin-film transistors studied by current–voltage and capacitance–voltage analyses

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