RF Magnetron Co-sputtering System Research Articles

Enhancement on the hardness and oxidation resistance property of TiN/Ag composite films for high temperature applications by addition of Si

Titanium nitride and silver (TiN/Ag) composite films exhibited the excellent self-lubricating properties in a wide temperature range due to the formation of the Ag rich tribolayer in the contact. However, Ag addition usually reduces the hardness and oxidation resistance properties of the films. In this paper, TiN/Ag/Si3N4 composite films were deposited using RF magnetron co-sputtering system to improve the mechanical and oxidation resistance properties of the TiN/Ag film. XRD and TEM analysis revealed that three-phases could be identified on the TiN/Ag/Si3N4 films: face-centered cubic (fcc) TiN, fcc-Ag and amorphous Si3N4 phases. The hardness of the TiN/Ag film increased from ∼16 GPa to ∼24 GPa for TiN/Ag/Si3N4 with 15.3 at.% of Si due to the formation of the nanocomposite structure. The addition of Si allowed a significant improvement on the oxidation resistance temperature, and effectively avoiding of Ag diffusion, and thereby contributing the stability of the hardness of the film after annealing treatment.

Electrochemical and Tribological Properties of TiSiCN Coatings in Coolant

TiSiCN coatings were prepared using DC and RF magnetron co-sputtering system. The influence of target powers on phase structures, mechanical properties, tribological and electrochemical properties were studied. The results indicated the coatings presented an amorphous structure, and the highest microhardness of 1566.4 HV was obtained at a target power of 200 W. In terms of the electrochemical properties in coolant, the higher charge transfer resistance of 2.64 × 107 Ωcm2 and the polarization resistance (~1.10 × 108 kΩ.cm2) were obtained at low target power, indicating a better corrosion resistance. Furthermore, the friction coefficient was 1.01 ~ 1.14 as sliding against SUS440C balls in air. In contrast, the friction coefficient decreased to 0.45 ~ 0.58 in coolant, and the wear mechanism changed from oxidation wear into abrasive wear.

Effect of thermal oxidation temperatures on the phase evolution and photocatalytic property of tungsten-doped TiO2 thin film

Tungsten-doped titanium dioxide (W-TiO2) thin films were successfully prepared on glass substrates by sputtering thermally oxidized W-doped titanium films in air. Tungsten-doped titanium films were deposited using a DC and RF magnetron cosputtering system. The effects of annealing treatment and W content on the W-TiO2 film microstructure were investigated. The crystalline structures, morphological features, and photocatalytic activity of the annealed W-TiO2 films were systematically studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and ultraviolet spectrophotometry. The results indicated that annealing at 550 °C clearly induced the formation of an anatase and rutile phase mixture in the 5.5 at. % W-TiO2 films, which directly affected photocatalytic activity. The W-TiO2 films showed good photocatalytic activity under UV-light irradiation, with a higher rate of methylene blue dye degradation than in the case of undoped TiO2.

Optical and electrical characteristics of Ga-Zn-O thin films prepared by RF magnetron co-sputtering system

We investigated the optical, electrical, and structural properties of GaZnO (GZO) thin films which have proven the potential uses in transparent thin film transistor. The doping concentrations of Ga atoms in GZO thin films were continuously controlled via the RF magnetron co-sputtering system in which ZnO target was sputtered at a fixed RF power 200 W, while Ga2O3 target was sputtered with a varied RF power from 30 W to 100 W. The highest electrical conductance and carrier mobility coincides with the dramatic optical band gap widening due to Burstein-Moss effect at the ∼3% atomic concentration of Ga doping. This study clearly indicates that the number of degenerate electrons in the conduction band increases sharply near the 3% doping level, but the band narrowing effect begins to dominate due to the electron-electron and electron-impurity interactions, resulting in the decrease of the carrier mobility beyond the optimized doping level.

The Achievement of a Zinc Oxide‐Based Homojunction Diode Using Radio Frequency Magnetron Cosputtering System

(Al + N)‐codoped p‐type zinc oxide (ZnO)/undoped n‐type ZnO homojunction structure was deposited onto Si (100) substrate by using radio frequency (rf) magnetron cosputtering system. Transparent indium tin oxide (ITO)‐ZnO cosputtered film was employed as the ohmic contact electrode to the n‐type ZnO film, and the specific contact resistance was optimized to 2.9 × 10−6 Ω cm2 after treating by a rapid thermal annealing (RTA) process at 400°C for 5 min under vacuum ambient. The ohmic contact behavior between the metallic Ni/Au and p‐ZnO film also was improved to 3.5 × 10−5 Ω cm2 after annealing at 300°C for 3 min under nitrogen ambient. The interfacial diffusion of these ohmic contact systems which led to the optimization of the specific contact resistances by the RTA process was investigated by the Auger electron spectroscopy (AES) depth profile measurements. The diode characteristics of the resulting p‐ZnO/n‐ZnO homojunction structure realized with these ohmic contact electrodes were confirmed by current‐voltage (I-V) measurement, which performed a forward turn‐on voltage of 1.44 V with a reverse current of 1.1 × 10−5 A at −2 V.

Transparent and conductive titanium indium zinc oxide/Ag/titanium indium zinc oxide multilayer films deposited by radio frequency magnetron co-sputtering

Multilayer transparent films with lower electrical resistance than the widely used transparent conductive electrodes, were prepared at room temperature on flexible PES [poly(ether sulfone)] substrates using an RF-magnetron co-sputtering system. The multilayered films consisted of three layers, titanium indium zinc oxide (TIZO)/Ag/TIZO. The optical and electrical properties of the multilayered TIZO/Ag/TIZO structure were investigated in relation to the thickness of each layer. A transparent and conductive film with a sheet resistance of 7.7Ω/□ and an average transmittance of 92% (normalized to the flexible PES substrate) at 550nm, was obtained at thicknesses of PES/TIZO(100nm)/Ag(10nm)/TIZO(40nm). The surface roughness (root mean square, RMS) values of the obtained multilayer films were below 1nm. Overall, the properties of the film were comparable or superior to those of other multilayer films such as indium tin oxide (ITO)/Ag//ITO, indium zinc oxide (IZO)/Ag/IZO, and indium zinc tin oxide (IZTO)/Ag/IZTO. For this reason, the new TIZO/Ag/TIZO multilayer film may serve as a viable, high-efficiency alternative for electrode applications in flexible photovoltaic cells.

Dependence of the Structural and Electrical Properties of Co-Sputtered Zn-Doped ITO Thin Films on the Composition and Oxygen Partial Pressure

Zn-In-Sn-O films were prepared at room temperature by combinatorial RF-magnetron co-sputtering system. The cationic contents of the films were varied using a compositionally combinatorial technique. The effects of the oxygen partial pressure and film compositionon the structural and electrical properties were investigated. The Zn-In-Sn-O films deposited at Ar gas atmosphere showed an amorphous phaseirrespective of the film composition. However, the amorphous Zn-In-Sn-O films with a Zn content below 30.0 at% were converted into a bixbyite type-ITO polycrystalline phase with an increase in the oxygen partial pressure. The resistivity, carrier concentration, and Hall mobility were strongly affected by the oxygen partial pressure and chemical composition of the film. At sufficiently high carrier densities above 5 × 10 18 cm ?3 , the conduction behavior of amorphous Zn-In-Sn-O film changes from thermally activated to degenerate band conduction accompanied with high mobility.

RF-magnetron sputtering을 이용한 TiIZO 기반의 산화물 반도체에 대한 연구

We fabricated thin film transistors (TFTs) using TiInZnO(TiIZO) thin films as active channel layer. The thin films of TiIZO were deposited at room temperature by RF-magnetron co-sputtering system from InZnO(IZO) and Ti targets. We examined the effects of titanium addition by X-ray diffraction, X-ray photoelectron spectroscopy and the electrical characteristics of the TFTs. The TiIZO TFTs were investigated according to the radio-frequency power applied to the Ti target. We found that the transistor on-off currents were greatly influenced by the composition of titanium addition, which suppressed the formation of oxygen vacancies, because of the stronger oxidation tendency of Ti relative to that of Zn or In. A optimized TiIZO TFT with rf power 40W of Ti target showed good performance with an on/off current ratio greater than , a field-effect mobility of 2.09 [], a threshold voltage of 2.2 [V] and a subthreshold swing of 0.492 [V/dec.].

Co-sputtering법으로 제작된 MgxZn1-xO 박막의 인가 파워에 따른 구조적 특성

The effect of co-sputtering condition on the structural properties of <TEX>$Mg_xZn_{1-x}O$</TEX> thin films grown by RF magnetron co-sputtering system was investigated for manufacturing UV LED. <TEX>$Mg_xZn_{1-x}O$</TEX> thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The <TEX>$Mg_xZn_{1-x}O$</TEX> thin films have sufficient crystallinity on the high ZnO power. The EDS analyzed showed that the Mg content in the <TEX>$Mg_xZn_{1-x}O$</TEX> films decreased from 3.99 to 24.27 at.% as the RF power of ZnO target increased. The Mg content in the <TEX>$Mg_xZn_{1-x}O$</TEX> films could be controlled by co-sputtering power.

MgxZn1-xO를 활용한 Multi-layer 구조 LED 특성에 관한 연구

The effect of co-sputtering condition on the structural properties of <TEX>$Mg_xZn_{1-x}O$</TEX> thin films grown by RF magnetron co-sputtering system was investigated for manufacturing ZnO/MgZnO structure LED. <TEX>$Mg_xZn_{1-x}O$</TEX> thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The ZnO thin films have sufficient crystallinity on the high RF power. As RF power of ZnO target increased, the contents of MgO in the <TEX>$Mg_xZn_{1-x}O$</TEX> film decreased. LED was manufactured using ZnO/MgZnO multi-layer on p-GaN/<TEX>$Al_2O_3$</TEX> substrate. Threshold voltage of multi-layer LED was appeared at 8 V, and it was luminesced at wave length of 550 nm.

Improvement of soft magnetic properties of CoFeSiB thin film by external magnetic field and Zr addition

Co40Fe17Si32B11 thin film (150 nm) was deposited by using an RF magnetron co-sputtering system on a Si (100) substrate. A self-designed substrate holder, including various hard magnets arranged around the substrates, was utilized so that various external magnetic fields could be applied to the Si substrates during the film deposition. By the effect of this deposition field, the applied field during the sample deposition, the squareness of the CoFeSiB thin film was significantly enhanced. From the angular analysis of the magnetic hysteresis curves from easy (parallel to external magnetic field) to hard (perpendicular to external magnetic field) direction of magnetization, it can be deduced that Co and Fe atoms were magnetically arranged to the easy magnetization axis by an external magnetic field which was induced during deposition. Also, the compositional cluster size of the CoFeSiB thin film was remarkably reduced by Zr addition, causing a decrease in the value of coercivity. These results suggest that apparent magnetic anisotropy was achieved, and the soft magnetic property of the CoFeSiB thin film was remarkably enhanced by the combination of the deposition field and Zr addition.

Annealing effect on the structural and optical properties of embedded Au nanoparticles in silicon suboxide films

Au/SiOx nanocomposite films have been fabricated by co-sputtering Au wires and SiO2 target using an RF magnetron co-sputtering system before the thermal annealing process at different temperatures. The structural and optical properties of the samples were characterized using X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), optical transmission, and reflection spectroscopy. XPS analysis confirms that the as-prepared SiOx films are silicon-rich suboxide films. FESEM images reveal that with an increase in annealing temperature, the embedded Au NPs tend to diffuse toward the surface of the SiOx films. In IR spectra, the intensity of the Si–O–Si absorption band increases with the annealing temperature. Optical spectra reveal that the position and intensity of the surface plasmon resonance (SPR) peak are dominated by the effect of the inter-particle distance and size of the Au NPs embedded in the SiOx films, respectively. The SPR absorption peak shows the blue-shift from 672 to 600 nm with an increase in annealing temperature. The growth of silica nanowires (SiOx NWs) is observed in the film prepared on a c-Si substrate instead of a quartz substrate and annealed at temperatures of 1000 °C.

Characteristics of NiO–AZO thin films deposited by magnetron co-sputtering in an O2 atmosphere

NiO–AZO thin films were prepared by DC and RF magnetron co-sputtering (MCS) system in an O2 atmosphere. The lowest resistivity of 1.75×10−1Ωcm was obtained in the film containing 1.94mol% Al. The I–V measurements of the p–n junction ((NiO–AZO)/ITO) revealed rectifying characteristics, demonstrating that the film possess p-type conductivity. These results showed good agreement with the X-ray photoelectron spectroscopy (XPS) data by the higher bond enthalpy of Ni–O (382±16.7kJ/mol) than Zn–O (159±4kJ/mol). Moreover, the NiO–AZO films had a higher work function than NiO, highlighting the potential applications of transparent contact electrodes in Gallium nitride LEDs.

SiC formation for a solar cell passivation layer using an RF magnetron co-sputtering system

In this paper, we describe a method of amorphous silicon carbide film formation for a solar cell passivation layer. The film was deposited on p-type silicon (100) and glass substrates by an RF magnetron co-sputtering system using a Si target and a C target at a room-temperature condition. Several different SiC [Si1-xCx] film compositions were achieved by controlling the Si target power with a fixed C target power at 150 W. Then, structural, optical, and electrical properties of the Si1-xCx films were studied. The structural properties were investigated by transmission electron microscopy and secondary ion mass spectrometry. The optical properties were achieved by UV-visible spectroscopy and ellipsometry. The performance of Si1-xCx passivation was explored by carrier lifetime measurement.

코스퍼터링법을 이용한 GaN LED 투명접촉전극용 NiO-AZO 박막의 제조 및 물성평가

NiO-AZO films were deposited on glass substrate by DC and RF magnetron co-sputtering system in pure gas without substrate heating during deposition. In order to control the chemical composition of the film, NiO target was supplied with constant RF power of 150 W and AZO target (doped with 2.98 at% aluminum) with DC power varied between 40 W to 80 W. Deposited NiO-AZO films were evaluated by structural and chemical analysis. With introducing AZO, XRD and XPS data reveal that NiO were supplied with more oxygen. these results could be strongly affected by the higher bond enthalpy of NiO compared to ZnO, which makes it possible for NiO to obtain excessive oxygen from ZnO.

Growth and Transport Properties of Sr-Doped Lanthanum Titanate Thin Films on LaAlO&lt;sub&gt;3&lt;/sub&gt;

Sr-doped LaTiO3 (SLTO) thin epitaxial films on LaAlO3 (100) have been fabricated by the off-axis rf magnetron co-sputtering system. The dopant Sr2+ ions were expected substituting La3+ ions in the films to introduce the hole carriers. The X-ray diffraction shows that the [001] direction of the SLTO films is perpendicular to the substrate surface. The in-situ grown specimens were measured the temperature dependence of resistivity and the Hall coefficients to study the transport properties. The Hall measurements show that the carrier is electron for Sr-doping over 16%. The temperature dependence of the resistance shows that the n-type films are metallic and deviate from free electron gas model obviously. We found the behaviour could be well described by the small-polaron coherent motion model.

Fabrication of Silicon Quantum Dots in Si3N4 Matrix Using RF Magnetron Co-Sputtering

Films consisting of a silicon quantum dot superlattice were fabricated by alternating deposition of silicon rich silicon nitride and <TEX>$Si_3N_4$</TEX> layers using an rf magnetron co-sputtering system. In order to use the silicon quantum dot super lattice structure for third generation multi junction solar cell applications, it is important to control the dot size. Moreover, silicon quantum dots have to be in a regularly spaced array in the dielectric matrix material for in order to allow for effective carrier transport. In this study, therefore, we fabricated silicon quantum dot superlattice films under various conditions and investigated crystallization behavior of the silicon quantum dot super lattice structure. Fourier transform infrared spectroscopy (FTIR) spectra showed an increased intensity of the <TEX>$840\;cm^{-1}$</TEX> peak with increasing annealing temperature due to the increase in the number of Si-N bonds. A more conspicuous characteristic of this process is the increased intensity of the <TEX>$1100\;cm^{-1}$</TEX> peak. This peak was attributed to annealing induced reordering in the films that led to increased Si-<TEX>$N_4$</TEX> bonding. X-ray photoelectron spectroscopy (XPS) analysis showed that peak position was shifted to higher bonding energy as silicon 2p bonding energy changed. This transition is related to the formation of silicon quantum dots. Transmission electron microscopy (TEM) and electron spin resonance (ESR) analysis also confirmed the formation of silicon quantum dots. This study revealed that post annealing at <TEX>$1100^{\circ}C$</TEX> for at least one hour is necessary to precipitate the silicon quantum dots in the <TEX>$SiN_x$</TEX> matrix.

Zinc Oxide-Based Schottky Diode Prepared Using Radio-Frequency Magnetron Cosputtering System

The rectifying property of a zinc oxide (ZnO)-based Schottky diode prepared using a radio-frequency (rf) magnetron cosputtering system was improved by enhancing the cosputtered ZnO crystal quality, thereby optimizing the ohmic contact resistance and compensating the Schottky contact surface states. An undoped ZnO layer with a high c-axis orientation and a low internal residual stress was achieved using a postannealing treatment. A homogeneous n-type ZnO–indium tin oxide (ITO) cosputtered film was deposited onto the undoped ZnO layer to optimize the ohmic contact behavior to the Al electrode. The Schottky contact surface of the undoped ZnO layer to the Ni/Au electrode was passivated using an oxygen plasma treatment. Owing to the compensation of the native oxygen vacancies (VO) on the undoped ZnO surface, the leakage current markedly decreased and subsequently led to a quality Schottky diode performance with an ideality factor of 1.23 and a Schottky barrier height of 0.82 eV.

The Study on SiCx Rear Passivation Synthesized by a RF Magnetron Co-Sputtering System

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Deposition of Amorphous Zinc Indium Tin Oxide and Indium Tin Oxide Films on Flexible Poly(ether sulfone) Substrate Using RF Magnetron Co-sputtering System

Zn–In–Sn-O (ZITO) and In–Sn-O (ITO) thin films were deposited at room temperature on poly(ether sulfone) (PES) substrates using a combinatorial rf magnetron co-sputtering system. The cationic contents of the films were varied using a compositionally combinatorial technique. The average optical transmittance of the ZITO films was >80% in the visible region. The ZITO films showed an amorphous phase regardless of the zinc content. A minimum resistivity of 4.1×10-4 Ω·cm was obtained at a zinc content of 8.9 at. % [Zn/(In + Zn + Sn)]. The amorphous ZITO films deposited on flexible substrates had good mechanical durability against external dynamic stress, as measured using a bending test. Overall, the characteristics of the ZITO films were comparable or superior to those of the amorphous ITO films, and thus ZITO films may serve as a viable, low-cost alternative for electrode applications in flexible organic light-emitting diodes or organic solar cells.