scholarly journals Defect Passivation and Carrier Reduction Mechanisms in Hydrogen-Doped In-Ga-Zn-O (IGZO:H) Films upon Low-Temperature Annealing for Flexible Device Applications

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 334
Rostislav Velichko ◽  
Yusaku Magari ◽  
Mamoru Furuta

Low-temperature activation of oxide semiconductor materials such as In-Ga-Zn-O (IGZO) is a key approach for their utilization in flexible devices. We previously reported that the activation temperature can be reduced to 150 °C by hydrogen-doped IGZO (IGZO:H), demonstrating a strong potential of this approach. In this paper, we investigated the mechanism for reducing the activation temperature of the IGZO:H films. In situ Hall measurements revealed that oxygen diffusion from annealing ambient into the conventional Ar/O2-sputtered IGZO film was observed at >240 °C. Moreover, the temperature at which the oxygen diffusion starts into the film significantly decreased to 100 °C for the IGZO:H film deposited at hydrogen gas flow ratio (R[H2]) of 8%. Hard X-ray photoelectron spectroscopy indicated that the near Fermi level (EF) defects in the IGZO:H film after the 150 °C annealing decreased in comparison to that in the conventional IGZO film after 300 °C annealing. The oxygen diffusion into the film during annealing plays an important role for reducing oxygen vacancies and subgap states especially for near EF. X-ray reflectometry analysis revealed that the film density of the IGZO:H decreased with an increase in R[H2] which would be the possible cause for facilitating the O diffusion at low temperature.

1989 ◽  
Vol 163 ◽  
S.N. Kumar ◽  
G. Chaussemy ◽  
A. Laugier ◽  
B. Canut ◽  
M. Charbonnier

AbstractAngle-resolved X-ray photoelectron spectroscopy characterization of the surface region of high-dose Sb+ ion implanted silicon, after rapid thermal treatments over various temperatures, is reported. The results obtained are compared with the Rutherford backscattering data and the capacitance-voltage measurements on the metal-oxide-semiconductor mesa structures built on them. Rapid anneal at 1100 °C of the 1.4×1016 Sb+/cm2 samples showed an anomalous deep oxygen diffusion inside the implanted region.

2005 ◽  
Vol 475-479 ◽  
pp. 3709-3712 ◽  
Li Ping Feng ◽  
Zheng Tang Liu

As a coating material with excellent optical and mechanical properties, silica films can be used as anti-reflective and protective layers on the windows and domes of sapphire. In this paper, the designed films of SiO2 have been prepared on sapphire wafers and hemisphere dome of sapphire by radio frequency magnetron reactive sputtering. Compositions and structure of SiO2 films were analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The refractive index of deposited films was measured and effects of the coatings on optical properties of sapphire have been studied. The results express that the refractive index of the films can be varied between 3.4 and 1.4 by changing the gas flow ratio. The deposited films can increase the transmission of sapphire in mid-wave IR greatly. The average transmittance of sapphire wafers coated with SiO2 films on both sides can be increased to 96.43 % in 3~5 µm.

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 955
Qide Yao ◽  
Xueli Ma ◽  
Hanxiang Wang ◽  
Yanrong Wang ◽  
Guilei Wang ◽  

The interface passivation of the HfO2/Si0.7Ge0.3 stack is systematically investigated based on low-temperature ozone oxidation and Si-cap methods. Compared with the Al2O3/Si0.7Ge0.3 stack, the dispersive feature and interface state density (Dit) of the HfO2/Si0.7Ge0.3 stack MOS (Metal-Oxide-Semiconductor) capacitor under ozone direct oxidation (pre-O sample) increases obviously. This is because the tiny amounts of GeOx in the formed interlayer (IL) oxide layer are more likely to diffuse into HfO2 and cause the HfO2/Si0.7Ge0.3 interface to deteriorate. Moreover, a post-HfO2-deposition (post-O) ozone indirect oxidation is proposed for the HfO2/Si0.7Ge0.3 stack; it is found that compared with pre-O sample, the Dit of the post-O sample decreases by about 50% due to less GeOx available in the IL layer. This is because the amount of oxygen atoms reaching the interface of HfO2/Si0.7Ge0.3 decreases and the thickness of IL in the post-O sample also decreases. To further reduce the Dit of the HfO2/Si0.7Ge0.3 interface, a Si-cap passivation with the optimal thickness of 1 nm is developed and an excellent HfO2/Si0.7Ge0.3 interface with Dit of 1.53 × 1011 eV−1cm−2 @ E−Ev = 0.36 eV is attained. After detailed analysis of the chemical structure of the HfO2/IL/Si-cap/Si0.7Ge0.3 using X-ray photoelectron spectroscopy (XPS), it is confirmed that the excellent HfO2/Si0.7Ge0.3 interface is realized by preventing the formation of Hf-silicate/Hf-germanate and Si oxide originating from the reaction between HfO2 and Si0.7Ge0.3 substrate.

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1099 ◽  
Song-Yi Ahn ◽  
Kyung Park ◽  
Daehwan Choi ◽  
Jozeph Park ◽  
Yong Joo Kim ◽  

In the present study, the effects of nitrogen incorporation on the transition of a p-type copper oxide semiconductor are investigated. The properties of sputtered copper oxide and nitrogen-incorporated copper oxide are evaluated and compared at various nitrogen gas flow rates. The results indicate that the addition of nitrogen results in an increased optical bandgap, accompanied by significantly reduced tail states compared to pristine copper oxide. In addition, X-ray diffraction and X-ray photoelectron spectroscopy reveal that the incorporation of nitrogen stimulates the transition from copper (II) oxide to copper (I) oxide.

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6789
Olga Netskina ◽  
Svetlana Mucha ◽  
Janna Veselovskaya ◽  
Vasily Bolotov ◽  
Oxana Komova ◽  

The development of solvent-free methods for the synthesis of catalysts is one of the main tasks of green chemistry. A nickel–alumina catalyst for CO2 methanation was synthesized by solid-state combustion method using hexakis-(imidazole) nickel (II) nitrate complex. Using X-ray Powder Diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Hydrogen temperature-programmed reduction (H2-TPR), it was shown that the synthesized catalyst is characterized by the localization of easily reduced nickel oxide on alumina surface. This provided low-temperature activation of the catalyst in the reaction mixture containing 4 vol% CO2. In addition, the synthesized catalyst had higher activity in low-temperature CO2 methanation compared to industrial NIAP-07-01 catalyst, which contained almost three times more hard-to-reduce nickel–aluminum spinel. Thus, the proposed approaches to the synthesis and activation of the catalyst make it possible to simplify the catalyst preparation procedure and to abandon the use of solvents, which must be disposed of later on.

2015 ◽  
Vol 761 ◽  
pp. 431-435
Zulkifli Rosli ◽  
Wai Loon Kwan ◽  
Mohd Warikh Ab Rashid ◽  
Jariah Mohd Juoi ◽  
Nayan Nafarizal

A nanocomposite TiAlBN (n-TiAlBN) coating has been successfully deposited via RF magnetron sputtering by varying the nitrogen-to-total gas flow ratio (RN) at a substrate temperature of 300 °C. The coating was deposited on AISI 316 substrates using a single Ti-Al-BN hot-pressed target. The crystal phases, grain size and chemical composition of the coatings were measured using the glancing angle X-ray diffraction analysis (GAXRD) and X-ray photoelectron spectroscopy (XPS). The grains size of the n-TiAlBN coating was found to be within the range of 3.5 to 5.7 nm calculated using Scherrer’s formula. The n-TiAlBN coating reached a nitride saturated state at a higher RN (e.g >15%) with the amount of boron concentration to be around 9 at. %. Further, reducing the RN (e.g. 5%) has increased the boron concentration to 16.17 at. %. This paper shows that by carefully control the nitrogen-to-total gas flow ratio (RN) in the n-TiAlBN coating, it indeed gives a significant effect on its crystallographic structure, grain size, and chemical compositions.

IUCrJ ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 128-135 ◽  
Aroa Morán-Ruiz ◽  
Aritza Wain-Martin ◽  
Alodia Orera ◽  
María Luisa Sanjuán ◽  
Aitor Larrañaga ◽  

The first fluorination of the cuspidine-related phases of Ln4(Al2O7□)O2 (where Ln = Sm, Eu, Gd) is reported. A low-temperature reaction with poly(vinylidene difluoride) lead to the fluorine being substituted in place of oxygen and inserted into the vacant position between the dialuminate groups. X-ray photoelectron spectroscopy shows the presence of the F 1s photoelectron together with an increase in Al 2p and rare-earth 4d binding energies supporting F incorporation. Energy-dispersive X-ray spectroscopy analyses are consistent with the formula Ln4(Al2O6F2)O2, confirming that substitution of one oxygen by two fluoride atoms has been achieved. Rietveld refinements show an expansion in the cell upon fluorination and confirm that the incorporation of fluoride in the Ln4(Al2O7□)O2 structure results in changes in Al coordination from four to five. Thus, the isolated tetrahedral dialuminate Al2O7 groups are converted to chains of distorted square-based pyramids. These structural results are also discussed based on Raman spectra.

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