Effect Of Sputtering Pressure Research Articles

Effect of sputtering pressure on some properties of chromium thin films obliquely deposited

Oriented columnar thin films provide a wide range of new properties linked to the large panel of available microstructures. The efficiency of the technique and thus the resulting structure, based on an incident flux of particles impinging on the substrate, depends on the distribution of the vapour source. The deposition pressure, which acts on the sputtered particles mean free path, is an important parameter, especially for sputtering processes. This study reports on the effect of different deposition pressures combined to a systematic change of the incidence angle of the sputtered particles, on the structural properties and electrical behaviours of obliquely sputtered chromium thin films. The results revealed higher performances and an enhanced control of the process at low sputtering pressure.

Effect of sputtering pressure and post-annealing on hydrophilicity of TiO 2 thin films deposited by reactive magnetron sputtering

A series of TiO 2 thin films was deposited onto glass substrates without intentional heating or biasing by magnetron sputtering of a titanium target using Ar/O 2 reactive mixtures over a broad range of total sputtering pressures from 0.12 Pa to 2.24 Pa. Each of the film types was deposited by the threshold poisoned mode at a specific given oxygen flow rate monitored in-situ by optical emission spectroscopy. Both the sputtering pressure and thermal annealing are the key factors for the TiO 2 films to yield fast-response superhydrophilicity with a water contact angle of 5°. The mechanism of superhydrophilicity for the TiO 2 films deposited by high-pressure sputtering will be discussed based on empirical studies of X-ray diffractometry, high-resolution scanning microscopy and atomic force spectroscopy.

Improving the Performance of Tin Oxide Thin-Film Transistors by Using Ultralow Pressure Sputtering

Thin-film transistors (TFTs) are fabricated with a tin oxide channel deposited by using ultralow pressure sputtering (ULPS). The effect of sputtering pressure on the device performance of the tin oxide TFTs was investigated. The TFTs with tin oxide channel deposited by conventional sputtering pressure did not show a promising performance. However, the saturation mobility and the threshold voltage of the ULPS-deposited TFTs were improved to and , respectively. The better device performance of the ULPS-deposited TFT was attributed to the reduced free electron density resulting from the formation of a nanocrystalline phase.

The effect of sputtering pressure on electrical, optical and structure properties of indium tin oxide on glass

Indium tin oxide (ITO) thin layers were deposited onto glass substrates by RF magnetron sputtering using different pressures. Subsequently, the films were annealed in a reducing atmosphere at 500 °C for 30 min. Electrical properties were measured by Hall Effect analysis and four-point probe measurements. Optical properties were determined by UV–Vis spectrophotometery. Film structures and compositions were analyzed by X-ray diffractometry and X-ray photoelectron spectroscopy, respectively. The effect of sputter pressure and additional anneals was investigated. The results revealed that the lowest resistivity of 1.69 × 10 − 4 Ω cm was achieved at low pressure (1.2 Pa) and the highest transmittance of ~ 90% was obtained after a second anneal. However, the second anneal decreased the mobility and the conductivity especially for high sputtering pressures. This study also describes the effect of Sn defect clustering on electrical properties of the ITO films.

Effect of sputtering pressure and rapid thermal annealing on optical properties of Ta 2O 5 thin films

Ta 2O 5 thin films were deposited by DC reactive magnetron sputtering followed by rapid thermal annealing(RTA). Influence of sputtering pressure and annealing temperature on surface characteristics, microstructure and optical property of Ta 2O 5 thin films were investigated. As-deposited Ta 2O 5 thin films are amorphous. It takes hexagonal structure ( δ-Ta 2O 5) after being annealed at 800 °C. A transition from δ-Ta 2O 5 to orthorhombic structure ( L-Ta 2O 5) occurs at 900–1 000 °C. Surface roughness is decreased after annealing at low temperature. Refractive index and extinction coefficient are decreased when annealing temperature is increased.

Effects of sputtering pressure on the field emission properties of N-doped SrTiO 3 thin films coated on Si tip arrays

The influence of sputtering pressure on the electron emission properties of Si tips coated with N-doped SrTiO 3 ultrathin films was investigated. X-ray diffraction studies revealed that the N-doped SrTiO 3 films deposited at different pressures remain the perovskite structure. However, the threshold electric field of electron emission decreased markedly when the sputtering pressure is increased, and reached a minimum value of 17.37 V/μm while deposited at 1.6 Pa. The decrease in the threshold field is attributed to the narrowed band gap and the lowered surface energy of SrTiO 3 thin films with nitrogen doped, as confirmed using spectroscopic ellipsometry and water contact angle measurement. Furthermore, it is revealed using XPS that such sputtering pressure dependence is accompanied with the change of nitrogen bonding state in the films, which changes from poorly screened γ-N 2 state to atomic β-N state when the sputtering pressure is increased. A mechanism of bonding and band-forming was proposed for the enhanced electron emission with nitrogen incorporation in the sputtered SrTiO 3 films.

Effect of sputtering pressure on pulsed-DC sputtered iridium oxide films

This paper reports the influence of the sputtering pressure, ranging from 5 to 50 mTorr using a mixture of Ar and O 2 (1:1), on the properties of the IrO x films deposited by pulsed-DC reactive sputtering. The sputtered IrO x films were characterized by surface analysis methods (scanning electron microscopy, atomic force microscopy, energy dispersive X-ray spectrometry, X-ray diffraction), four-point probe method, and electrochemical techniques (cyclic voltammetry and electrochemical impedance spectroscopy). The optimal sputtering pressure was identified to be 5 mTorr at which the activated IrO x film showed highest charge storage capacity of 28.3 mC/cm 2, which was almost three times higher than that of samples deposited at 50 mTorr. The IrO x films deposited at low pressure showed excellent mechanical electrical and electrochemical characteristics and hence can be recommended as an ideal stimulation electrode material for neuroprosthetic applications.

Effects of sputtering pressure and thickness on properties of ZnO:Al films deposited on polymer substrates

Highly conducting and transparent aluminum doped zinc oxide (ZnO:Al) thin films have been deposited on polyimide substrate by r.f. magnetron sputtering at room temperature. The influence of sputter pressure and thickness on the structural, electrical, and optical properties of ZnO:Al films deposited on polyimide substrate is reported. The crystallinity and degree of orientation was increased by decreasing the sputter pressure. For higher sputtering pressures an increase on the resistivity was observed due to a decrease on the mobility and the carrier concentration. As the film thickness was increased, the crystallite sizes were increased, but the average transmittance in the wavelength range of the visible spectrum was decreased. The electrical performances of the ZnO:Al films deposited on glass substrates are slightly worse than the ones of the films deposited on polyimide substrates with same thickness. The lowest resistivity of 8.6 × 10−4 Ω cm can be obtained for films deposited on glass substrate with the thickness of 800 nm.

The properties of TiN thin films deposited by pulsed direct current magnetron sputtering

This work investigated the effect of sputtering pressure on the properties of titanium nitride films deposited by pulsed dc (direct current) magnetron sputtering. The pulse frequency was 60 kHz, and reverse time of pulse was 5 µs. The preferred-orientation of titanium nitride films transforms from (111) to (200) when the sputtering pressure decreases. At the same time, the deposition rate and hardness of films increase, while the resistivities of titanium nitride films decrease. Comparing with the continuous dc sputtering, the titanium nitride films prepared by pulsed dc process exhibit better properties. Although both pulsed and continuous dc sputtered films possess the same low resistivity 23 µΩ-cm under 0.75 Pa, the resistivities of pulsed dc films are relatively stable with respect to the variation of sputtering pressure. The pulsed dc films also exhibit higher hardness than continuous dc films.

Effects of sputtering pressure on the characteristics of lithium ion conductive lithium phosphorous oxynitride thin film

Lithium phosphorous oxynitride(Lipon) thin films as a lithium ion conductive electrolyte were prepared by radio frequency reactive sputtering in N2 plasma. The properties of the amorphous Lipon solid electrolyte were investigated as a function of N2 pressure during reactive sputtering. The ionic conductivity and the electrochemical stability of Lipon thin films improved drastically as the N2 pressure decreased. The ionic conductivity closed to 10−6 S cm−1 and obtained a stability window of 1.0–5.0 V with an N2 pressure of 5 mTorr, where the number of nitrogen bonds between the phosphate groups were more than those formed at higher pressure. It was possible to fabricate the Li//LiCoO2 complete thin film battery using this Lipon solid electrolyte, which exhibited excellent discharge characteristics close to the theoretical capacity (ca. 69 uAhcm−2−um−1) and showed a considerably high rate capability.

Effect of sputtering pressure and annealing temperature on the properties of indium tin oxide thin films

Indium tin oxide (ITO) thin films were deposited on glass substrates by RF sputtering system at different sputtering pressure (SP) (20–34 mTorr) and room temperature. The sputtering pressure effects on the deposition rate, electro-optical and structural properties of the as-deposited films were systematically investigated. The optimum sputtering pressure of 27 mTorr, giving a good compromise between electrical conductivity and optical transmittance was found to deposit films. The films were heat-treated in vacuum (200–450 °C) and their electro-optical and structural properties investigated with temperature. A criterion factor Q, which is the ratio between the normalized average transmission to normalized resistivity was defined. It has been observed that Q has its maximum value for heat treatment at 400 °C and the X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis proves the films have preferred crystal growth towards (2 2 2) direction and average size of grains are 35–40 nm.

Effects of sputtering pressure on compositions and structures of fresnoite thin films

Fresnoite is a new ferroelectric mineral which has potential applications in acoustic wave devices and non-linear optical devices. In this paper, fresnoite thin films were fabricated by r.f. sputtering. The experiments indicated that the working pressure influences significantly on the composition and structure of the thin films. As the pressure decreases, the deficiency of Ba and the excess of Si in the thin films were controlled. A thin film with chemical stoichiometry was obtained at the pressure of 0.3 Pa. Besides, the decrease of the pressure improved the crystallinity and orientation of the thin films. These improvements on the stoichiometry and microstructure of the fresnoite thin films are attributed to the increase of the mean free path and the impacting energy of ions at low working pressure.

Effect of sputtering pressure on residual stress in Ni films using energy-dispersive x-ray diffraction

A procedure for determining the residual stress in thin films using energy dispersive x-ray diffraction was investigated. The effect of the sputtering pressure on the residual stress in dc magnetron sputtered Ni films was studied in greater detail using this approach. The behavior reported suggested the possibility of controlling or influencing the sign and/or magnitude of the residual stress. In addition, the stress variation with increasing negative bias voltage is also presented. In the range studied, between −15 and −150 V, residual stress is always tensile.

Magnetic and structural characteristics of exchange biasing systems based on NiMn antiferromagnetic films

We have investigated the magnetic and the structural characteristics of bi-layer exchange biasing (EB) systems NiMn–Co as function of the antiferromagnetic (AFM) film deposition parameters and of the post-deposition annealing and field-cooling procedures. The effects of sputtering pressure, growth rate, seed layer and of the annealing parameters were studied by X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Magneto-Optical Kerr (MOKE) effect measurements. The results yielded optimised deposition conditions and permitted us to establish efficient annealing and field-cooling procedures. The best obtained EB systems with 5 nm Co film reveal coercive field H c⩾35 Oe and exchange bias field H EB⩾95 Oe and have good stability in air up to at least 200°C. The obtained magnetic characteristics are closely correlated with the crystalline structure of the as-deposited samples and with the phase transformation effects. According to our results, the as-deposited samples are a mixture of a non-equilibrium FCC NiMn phase (quenched by the sputtering deposition process) and a variable amount of the equilibrium face centred tetragonal (FCT) phase. The ratio of these two phases depends on the deposition conditions—the amount of the FCT NiMn phase is larger if deposition conditions closer to equilibrium have been used, especially at higher sputtering gas pressure and higher deposition rates. The annealed samples contain dominantly the FCT AFM phase as confirmed by XRD and TEM-diffraction analyses. The transition to this AFM state depends on the initial structure of the as-grown samples and, respectively, on their deposition conditions.

Electrical and optical properties of InN films prepared by reactive sputtering

Indium nitride thin films were prepared by the reactive magnetron sputtering method. The indium target was sputtered by pure nitrogen gas. The effects of sputtering pressure ( P) on the structural, optical and electrical properties of the films were investigated. With increasing P, the deposition rate decreased, and the film structure changed from crystalline phase with a hexagonal wurtzite structure to amorphous one. The energy bandgaps in crystalline films are around 1.9 eV, whereas optical bandgaps in amorphous films are larger than this value. The electrical conductivity, Hall mobility and carrier concentration of the films depend on P and they take minima at P∼4 Pa

Physical Properties of Zinc Oxide Films Prepared by dc Reactive Magnetron Sputtering at Different Sputtering Pressures

Thin films of zinc oxide were deposited by dc reactive magnetron sputtering onto glass substrates held at a temperature of 663 K and oxygen partial pressure of 1x10 -3 mbar, and at different sputtering pressures in the range 3x10 -2 - 10x10 -2 mbar. The effect of sputtering pressure on the structural, electrical and optical properties of the films were systematically studied. The films were polycrystalline in nature with preferred (002) orientation. The temperature dependence of Hall mobility indicated that the grain boundary scattering of the charge carriers are predominant in these films. The films formed at a sputtering pressure of 6x10 -2 mbar showed a low electrical resistivity of 6.9x10 -2 Ω.cm, optical transmittance of 83% with an optical band gap of 3.28 eV.

マグネトロンスパッタ法によるＩｎＮ薄膜の作成と特性

Indium nitride thin films were prepared by the reactive magnetron sputtering method. The indium target was sputtered by pure nitrogen gas. The effects of sputtering pressure P on the structural, optical and electrical properties of the films were investigated. With increasing P, the depo-sion rate of the films decreased, and the film structure changed from crystalline phase with a hexagonal wurtzite structure to amorphous one, together with the increase in the bandgap. It is found that the electrical conductivity, carrier concentration and Hall mobility showed minimum against P.

Effect of sputtering pressure on the structure and current-perpendicular-to-the-plane magnetotransport of Co/Ag multilayered films

Co/Ag multilayers have been sputter-deposited at pressures ranging from 0.86 to 10 mTorr, and magnetotransport measurements have been performed with the current both perpendicular to the plane (CPP) and in the plane (CIP) of the samples. X-ray-scattering studies indicate that the roughness of the interfaces is influenced by the presence of the Nb layers used to make electrical contact for the CPP measurements, as well as by the sputtering pressure. For samples deposited at higher sputtering pressures, the Nb contact layers also influence the low-temperature coercive field of the multilayers. The CPP-giant magnetoresistance is observed to decrease with increasing sputtering pressure and, in the case of the signal observed after cycling to above the saturation field, this decrease is found to come in roughly equal measure from an increase in the high field-saturated specific resistance and a decrease in the field-dependent specific resistance. Making use of the direct connection between microscopic physical parameters and experimental results available through the CPP geometry, we show that both of these changes arise primarily from increased scattering in both spin channels. We see very little, if any, evidence for a change in the spin-dependent scattering with sputtering pressure.

CoPt alloy films with saturated remanence ratio prepared by sputtering a composite target

CoPt alloy films with perpendicular magnetic anisotropy, 100% remanence, large coercivity and Kerr rotation were prepared by sputtering a composite target without any buffer layer. Effects of sputtering pressure, substrate temperature, film thickness and Co content on the magnetic and magnero-optical properties of the films are studied. X-ray diffraction analysis shows that the perpendicular magnetic anistropy in CoPt alloy films is not directly related to the ordered CoPt 3 L1 2.

Large area deposition of ITO films by cluster type sputtering system

The preparation of large area ITO films for transparent electrodes of liquid crystal display (LCD) devices by a cluster type sputtering system (Anelva C-3500) was carried out. Effects of sputtering pressure and introduced oxygen gas flow rate at a low substrate temperature of 10°C on crystal structure, electrical property and etching properties were measured. Amorphous films could be obtained at a sputtering pressure higher than 2.6 Pa and an introduced oxygen gas flow rate lower than 0.8 sccm. During the measurement of etching properties of these films, an etching rate > 80 nm/s and a uniformity of about ±20% were obtained. The sheet resistance could not be reduced to a practical level for LCD devices even after annealing. To obtain a uniform and high etching rate and a low sheet resistance at a practical level, the parameters should be optimized. Although the film was not completely amorphous, an average value of 27 nm/s and a uniformity of ±23.5% for the etching rate was obtained within an area of 370 × 470 mm on a 400 × 500 mm substrate and an average sheet resistance of about 30 ω/□ was also obtained after annealing.