• Korean Journal of Materials Research
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• v.33 no.11
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• pp.491-496
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• 2023

As the demand for p-type semiconductors increases, much effort is being put into developing new p-type materials. This demand has led to the development of novel new p-type semiconductors that go beyond existing p-type semiconductors. Copper iodide (CuI) has recently received much attention due to its wide band gap, excellent optical and electrical properties, and low temperature synthesis. However, there are limits to its use as a semiconductor material for thin film transistor devices due to the uncontrolled generation of copper vacancies and excessive hole doping. In this work, p-type CuI semiconductors were fabricated using the chemical vapor deposition (CVD) process for thin-film transistor (TFT) applications. The vacuum process has advantages over conventional solution processes, including conformal coating, large area uniformity, easy thickness control and so on. CuI thin films were fabricated at various deposition temperatures from 150 to 250 ℃ The surface roughness root mean square (RMS) value, which is related to carrier transport, decreases with increasing deposition temperature. Hall effect measurements showed that all fabricated CuI films had p-type behavior and that the Hall mobility decreased with increasing deposition temperature. The CuI TFTs showed no clear on/off because of the high concentration of carriers. By adopting a Zn capping layer, carrier concentrations decreased, leading to clear on and off behavior. Finally, stability tests of the PBS and NBS showed a threshold voltage shift within ±1 V.

• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.194-200
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• 2002

MOCVD(metal-organic chemical vapor deposition) copper thin film was annealed at various conditions and the eletrical properties and micro-structures were investigated to find the optimal annealing condition and its effect. Cu thin film annealed at Ar 1 torr, $400^{\circ}C$ had the most improved resistivity of 1.98 $\mu\Omega$cm, and texture; the ratio of $I_{(111)}/I_{(200)}$ was varied from 2.03 to 3.11, and Cu thin film annealed at Ar 1 torr, $450^{\circ}C$ had the largest grain size and uniformity. After the annealing, the EM(electromigration) test was followed to ensure the improved properties by annealing. Compare to other conditions, Cu patterns annealed at Ar 1 torr, $400 ^{\circ}C$ had the most improved properties when it came to the EM resistance, which was due to the low resistivity, the preferential evolution of texture to (111) plane, and the reduction of surface roughness of annealed copper film.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.63-69
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• 2022

Preparing various types of thin films of oxide semiconductors is a promising approach to fabricate efficient photoanodes and photocathodes for hydrogen production via photoelectrochemical (PEC) water splitting. In this work, we investigate the feasibility of an efficient photocathode for PEC water reduction of a p-type oxide semiconductor cupric oxide (CuO) thin film prepared via a facile method combined with sputtering Cu metallic film on fluorine-doped thin oxide (FTO) coated glass substrate and subsequent thermal oxidation of the sputtered Cu metallic film in dry air. Characterization of the structural, optical, and PEC properties of the CuO thin film prepared at various Cu sputtering powers reveals that we can obtain an optimum CuO thin film as an efficient PEC photocathode at a Cu sputtering power of 60 W. The photocurrent density and the optimal photocurrent conversion efficiency for the optimum CuO thin film photocathode are found to be -0.3 mA/cm² and 0.09% at 0.35 V vs. RHE, respectively. These results provide a promising route to fabricating earth-abundant copper-oxide-based photoelectrode for sunlight-driven hydrogen generation using a facile method.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.188-188
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• 2011

Recently, scaling down of ULSI (Ultra Large Scale Integration) circuit of CMOS (Complementary Meta Oxide Semiconductor) based electronic devices, the electronic devices, become much faster and smaller size that are promising property of semiconductor market. However, very narrow interconnect line width has some disadvantages. Deposition of conformal and thin barrier is not easy. And metallization process needs deposition of diffusion barrier and glue layer for EP/ELP deposition. Thus, there is not enough space for copper filling process. In order to get over these negative effects, simple process of copper metallization is important. In this study, Cu-V alloy layer was deposited using of DC/RF magnetron sputter deposition system. Cu-V alloy film was deposited on the plane SiO2/Si bi-layer substrate with smooth surface. Cu-V film's thickness was about 50 nm. Cu-V alloy film deposited at $150^{\circ}C$. XRD, AFM, Hall measurement system, and AES were used to analyze this work. For the barrier formation, annealing temperature was 300, 400, $500^{\circ}C$ (1 hour). Barrier thermal stability was tested by I-V(leakage current) and XRD analysis after 300, 500, $700^{\circ}C$ (12 hour) annealing. With this research, over $500^{\circ}C$ annealed barrier has large leakage current. However vanadium-based diffusion barrier annealed at $400^{\circ}C$ has good thermal stability. Therefore thermal stability of vanadium-based diffusion barrier is desirable for copper interconnection.

• Journal of Electrochemical Science and Technology
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• v.2 no.4
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• pp.204-210
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• 2011

Thin film electrodes have been intensively studied for active materials and current collectors to enhance the electrochemical performance. Here, porous structures of nickel-based oxide films, consisting of nickel oxide and copper (II) oxide, which was derived from the copper substrate during the annealing process, were deposited on metallic copper foils. The half-cell tests revealed excellent capacity retention after $80^{th}$ charge/discharge cycles. Some films showed an excess of the theoretical capacity of nickel oxides, which mainly originate from partially oxidized copper substrates during annealing. These results exhibit that both a preparation method of an active materials and partially oxidized current collectors could be important roles to apply thin film electrodes.

• Korean Journal of Materials Research
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• v.9 no.6
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• pp.583-588
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• 1999

The characteristics of copper thin films and pattern filling capability were investigated by ECD. Prior to deposition of copper film, seed-Cu/Ta(TaN)/$SIO_2$(BPSG)/Si structure was manufactured. Copper deposition was performed with various current waveforms(DC/PC, 1~10,000Hz) and current densities(10~60 mA/$\textrm{cm}^2$) after pretreatment (Oxident removal, wetting) of seed-layer. Conformal pattern filling was performed using PC method with fast deposition rate of 6,000~8,000$\AA$/min. Heat-treated($450^{\circ}C$, 30min) copper films showed good resistivities of 1.8~2.1$\mu$$\Omega$.cm. According to the XRD analysis, (111)-preferred orientation of copper film was found in ECD-Cu/seed-Cu/Ta/$Sio_2$/Si structure. Also, we have successfully achieved to fill via holes with 0.35$\mu\textrm{m}$ width and 4:1 aspect ratio.

• Korean Journal of Materials Research
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• v.28 no.1
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• pp.32-37
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• 2018

We report on the efficient detection of NO gas by an all-oxide semiconductor p-n heterojunction diode structure comprised of n-type zinc oxide (ZnO) nanorods embedded in p-type copper oxide (CuO) thin film. The CuO thin film/ZnO nanorod heterostructure was fabricated by directly sputtering CuO thin film onto a vertically aligned ZnO nanorod array synthesized via a hydrothemal method. The transport behavior and NO gas sensing properties of the fabricated CuO thin film/ZnO nanorod heterostructure were charcterized and revealed that the oxide semiconductor heterojunction exhibited a definite rectifying diode-like behavior at various temperatures ranging from room temperature to $250^{\circ}C$. The NO gas sensing experiment indicated that the CuO thin film/ZnO nanorod heterostructure had a good sensing performance for the efficient detection of NO gas in the range of 2-14 ppm under the conditions of an applied bias of 2 V and a comparatively low operating temperature of $150^{\circ}C$. The NO gas sensing process in the CuO/ZnO p-n heterostructure is discussed in terms of the electronic band structure.

• Journal of the Microelectronics and Packaging Society
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• v.9 no.3
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• pp.1-6
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• 2002

A low temperature process technology of copper thin films has been developed by a chemical vapor deposition technology for multi-level metallzations in ULSI fabrication. The copper films were deposited on TiN/Si substrates in helium atmosphere with the substrate temperature between $130^{\circ}C$ and $250^{\circ}C$. In order to get more reliable metallizations, effects on the post-annealing treatment to the electrical properties of the copper films have been investigated. The Cu films were annealed at the $5 \times10^{-6}$ Torr vacuum condition and the electrical resistivity and the nano-structures were measured for the Cu films. The electrical resistivity of Cu films shown to be reduced by the post-annealing. The electrical resistivity of 2.0 $\mu \Omega \cdot \textrm{cm}$ was obtained for the sample deposited at the substrate temperature of $180^{\circ}C$ after vacuum annealed at $300^{\circ}C$. The resistivity variations of the films was not exactly matched with the size of the nano-structures of the copper grains, but more depended on the contamination of the copper films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.526-530
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• 2004

We report the space charge and the surface potential of the interface between metal and CuPc according to isotropic property and different metal by measuring the microwave reflection coefficients $S_{11}$ of copper(II)-phthalocyanine(CuPc) thin films by using a near-field microwave microscope(NSMM) in order to understand. CuPc thin films were prepared on gold and aluminium substrates using a thermal evaporation method. Two kinds of CuPc thin films were prepared. One was deposited on preheated substrate at $150^{\circ}C$ and the other was annealed after deposition by using thermal evaporation methods. The microwave reflection coefficients $S_{11}$ of CuPc thin films were changed by the dependence on the heat treatment conditions. By comparing reflection coefficient $S_{11}$ we measured electrical conductivity of CuPc thin films and studied this results with respect to the surface potential and space charge of the interface between metal and CuPc thin films.

• Laser Solutions
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• v.16 no.2
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• pp.7-11
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• 2013

Recently advanced laser processing is widely introduced to improve the efficiency of micro part production and to reduce the rate of inferior goods. In this paper the trend of delamination of single layer with both thin copper and polyimide according to the variation of copper thickness was investigated using the coupled thermal-structural analysis of ANSYS. From these analyses results, some conclusions were obtained. Firstly, the maximum temperature was increasing with respect to decrease of copper thickness. Secondly the maximum strain which was in general estimation the main effect of the delamination was observed in case of the copper thickness of $5{\mu}m$. Finally the trend of the delamination was decreasing with increasing the thickness of copper layer.