Effect of electron beam irradiation on structure and properties of SiCN thin films prepared by plasma assisted radio frequency magnetron sputtering

Silicon carbon nitride thin films were deposited on Si (100) substrate at room temperature by plasma assisted radio frequency magnetron sputtering. The bonding structure and properties of SiCN films irradiated by pulsed electron beams were studied by means of X-ray photoelectron spectroscopy and nano-indentation. The results showed that electron beam irradiation had a great effect on the structure and property of the films. Under sputtering gas pressure of 3.7 Pa, a transition from the (Si,C)N_x bonded structure to the (Si,C)₃N₄ bonded structure was found in the SiCN thin film with electron beam irradiation. At sputtering gas pressure of 6.5 Pa, the enhancement of hardness in the SiCN film after treatment with electron beam irradiation resulted from the promotion of the sp³-hybridization of carbons bonds.     

Ion beam deposition of α-Ta films by nitrogen addition and improvement of diffusion barrier property

Ta thin films were deposited on Si (100) substrates by an ion beam deposition method at various substrate bias voltages under Ar + N₂ atmosphere with different pressure ratios of Ar and N₂. The effects of nitrogen pressure in the plasma gas and the substrate bias voltage on the surface morphology, crystalline microstructure, electrical resistivity and diffusion barrier property were investigated. It was found that the fraction of a metastable β-phase in the Ta film deposited at the substrate bias voltage of − 50 V films decreased by adding nitrogen gas, while the α-Ta phase became dominant. As a result, the Ta films deposited at the substrate bias voltage of − 50 V under Ar (9 Pa) + N₂ (3 Pa) atmosphere showed a dominant α-phase with good surface morphology, low resistivity, and superior thermal stability as a diffusion barrier.     

Irradiation induced effects on Ni3N/Si bilayer system

The irradiation effect in Ni₃N/Si bilayers induced by 100 MeV Au ions at fluence 1.5 × 10¹⁴ ions/cm² was investigated at room temperature. Grazing incidence X-ray diffraction determined the formation of Ni₂Si and Si₃N₄ phases at the interface. The roughness of the thin film was measured by atomic force microscopy. X-ray reflectivity was used to measure the thickness of thin films. X-ray photoelectron spectroscopy has provided the elemental binding energy of Ni₃N thin films. It was observed that after irradiation (Ni 2p_3/2) peak shifted towards a lower binding energy. Optical properties of nickel nitride films, which were deposited onto Si (100) by ion beam sputtering at vacuum 1.2 × 10⁻⁴ torr, were examined using Au ions. In-situ I–V measurements on Ni₃N/Si samples were also undertaken at room temperature which showed that there is an increase in current after irradiation.     

Preparation of homogeneous VOX thin films by ion beam sputtering and annealing process

Polycrystalline VO_x thin films that were prepared for thermal-sensitive material of far infrared sensor had been deposited on Si substrates by ion beam sputtering deposition. Scanning electron microscopy images indicated that VO_x thin films (oxygen pressure of 1.5×10⁻³ Pa) were grown into compact and ultra-fine grains (?50 nm), the film surfaces seemed smooth and uniform. Four-point probe measurements showed that the homogeneity of the films was better than 98% in a size of 30×30 mm². The four-point probe measurement on hot plate presented the sheet resistance and the temperature coefficient of resistance of the VO_x thin film that were 50 kΩ/square and −0.021 K⁻¹ at 28°C, respectively. In addition, some samples annealed in Ar atmosphere had their resistance decreased. Thus, vanadium oxide films containing more amount VO₂ were obtained.     

Control of electrical resistivity of TaN thin films by reactive sputtering for embedded passive resistors

Tantalum nitride thin films were deposited by radio frequency (RF) reactive sputtering at various N₂/Ar gas flow ratios and working pressures to examine the change of their electrical resistivity. From the X-ray diffraction (XRD) and four-point probe sheet resistance measurements of the TaN_x films, it was found that the change of the crystalline structures of the TaN_x films as a function of the N₂ partial pressure caused an abrupt change of the electrical resistivity. When the hexagonal structure TaN thin films changed to an f.c.c. structure, the sheet resistance increased from 16 Ω/sq to 1396 Ω/sq. However, we were able to control the electrical resistivity of the TaN thin film in the range from 69 Ω/sq to 875 Ω/sq, with no change in crystalline structure, within a certain range of working pressures. The size of the grains in the scanning electron microscopy (SEM) images seemed to decrease with the increase of working pressure.     

Orthogonal analysis for perovskite structure microwave dielectric ceramic thin films fabricated by the RF magnetron-sputtering method

The perovskite structure microwave dielectric ceramic thin films have been deposited by radio frequency (RF) magnetron sputtering on SiO₂(110) substrates. Subsequently, orthogonal analysis has been adopted to optimize the process parameters. The experimental results indicate that sputtering pressure has the greatest impact on comprehensive evaluation indicators such as the film quality, whereas sputtering power has a lower effect; the ratio of O₂/Ar and substrate temperature have the least impact on the process. Thus, the optimal process parameters to prepare perovskite structure dielectric thin films by RF magnetron sputtering are as follows: 200 W of sputtering power, 0.25 Pa of sputtering pressure, Ar as working gas, and substrate temperature of 610 °C.     

Preparation and properties of Mg0.2Zn0.8O:Al UV transparent conducting thin films deposited by RF magnetron sputtering at room temperature with rapid annealing

Mg_0.2Zn_0.8O:Al UV transparent conducting thin films were deposited by RF magnetron sputtering at room temperature with a rapid annealing process. Effects of sputtering power, argon gas pressure and annealing temperature on structure, optical and electrical properties of Mg_0.2Zn_0.8O:Al films were investigated. The experimental results show that Mg_0.2Zn_0.8O:Al thin films exhibit high preferred c-axis-orientation. The sputtering power, argon gas pressure and annealing temperature all exert a strong influence on the electrical resistivity of Mg_0.2Zn_0.8O:Al thin films due to the variation of carrier concentration and mobility in films derived from the change of effective doping and crystallinity. The lowest electrical resistivity of Mg_0.2Zn_0.8O:Al thin films is 3.5 × 10⁻³ Ω·cm when the sputtering power is 200 W, the argon gas pressure is 2.0 Pa and the annealing temperature is above 500 °C. The transparent spectrum range of Mg_0.2Zn_0.8O:Al thin films extend to ultraviolet band and the optical transmittance is between 80 and 90%, but the sputtering power, argon gas pressure and annealing temperature all exert little influence on optical transmittance.     

Effect of sputtering pressure on the properties of ZnMgO: Ti transparent conducting thin films

ZnMgO: Ti transparent conducting thin films have been deposited on glass substrates by DC-magnetron sputtering, and the effects of sputtering pressure on their properties have been investigated. Electrical resistivity as low as 7.84*10⁻⁴Ω cm was achieved for ZnMgO: Ti thin film. All thin films provided high optical transparencies in the visible region. Thin films deposited at 6 Pa, 8 Pa and 10 Pa showed “blue shift”. These results have not only clarified the effects of the sputtering pressure on the properties of ZnMgO: Ti films, but also revealed the potential of ZnMgO: Ti films in solar cells application. Efficiency of solar cells may be improved by choosing ZnMgO: Ti thin film as transparent electrode.     

Fabrication of high frequency ZnO thin film SAW devices on silicon substrate with a diamond-like carbon buffer layer using RF magnetron sputtering

Diamond-like carbon (DLC) film is a promising candidate for surface acoustic wave (SAW) device applications because of its higher acoustic velocity. A zinc oxide (ZnO) thin film has been deposited on DLC film/Si substrate by RF magnetron sputtering; the optimized parameters for the ZnO sputtering are RF power density of 0.55 W/cm², substrate temperature of 380 °C, gas flow ratio (Ar/O₂) of 5/1 and total sputter pressure of 1.33 Pa. The results showed that when the thickness of the ZnO thin films was decreased, the phase velocity of the SAW devices increased significantly.     

The effect of argon pressure, residual oxygen and exposure to air on the electrical and microstructural properties of sputtered chromium thin films

Chromium thin films were deposited on SiO₂/Si wafers using two sputtering systems with different levels of cleanliness, and at argon sputtering pressures varying between 0.13 and 0.93 Pa. Films from the two systems grown under identical sputtering conditions had significantly different resistivity values that are shown to be due to differences in residual oxygen in the chambers. Electrical transport measurements were conducted on the series of grown films to investigate the influence of argon pressure on film electrical resistivity. The films morphology, microstructure and composition were characterized using scanning electron microscopy and X-ray photoelectron spectroscopy. Significant differences were found in Cr thin films sputtered at different sputtering pressures; differences in resistivity performance and microstructure were noted. This change was shown to be due to the transition from porous structure to a denser microstructure. The Cr films sputtered at high pressure contained large quantities of oxygen when exposed to air. Some of the oxygen is added to the film during the deposition depending on the deposition rate and the base pressure of the sputtering system. The rest is incorporated into the film once it is exposed to air. The amount of oxygen added at this stage depends on the structure of the film and would be minimal for the films deposited at low sputtering pressures.     

Stress tuning in AIN thin films

Aluminium nitride films were deposited on fused silica by reactive dc magnetron sputtering from an Al-target in an Ar/N₂ atmosphere. In-situ measurements during deposition provided data concerning mechanical stresses inherent to the growing thin films. By variation of both the gas composition (Ar, N₂) and the total gas flow in the vacuum chamber, the occuring intrinsic stresses could be shifted in magnitude and direction. Stress values of the AIN films ranged from ?0.9 GPa (compressive) to +1.2 GPa (tensile) when the Ar/N₂ ratio was varied between 3:1 and 1:3 for the different total gas flows of 50 sccm, 100 sccm, and 200 sccm (corresponding to total gas pressures of approximately 2 × 10^?1 Pa, 4 × 10^?1 Pa, and 8 × 10^?1 Pa respectively). Investigations of optical and structural film properties were carried out and the results were related to the observed film stress.     

Growth of highly oriented LiTaO3 thin film on Si with amorphous SiO2 buffer layer by pulsed laser deposition

High-quality single-phase, c-axis textured LiTaO₃ thin films have been deposited on Si(100) substrate with amorphous SiO₂ buffer layer for optic waveguide application by pulsed laser deposition under optimized conditions of 30 Pa oxygen pressure and 650 °C. The amorphous SiO₂ buffer layer with a thickness of 100 nm was coated on the Si(100) by thermal oxidation at 1000 °C. Li-enriched LiTaO₃ ceramic target was used during the deposition. In order to study the influence of oxygen pressure on the orientation, crystallinity and morphology, different oxygen pressures (10 Pa, 20 Pa, 30 Pa and 40 Pa) were used. X-ray diffraction (XRD) results showed that LiTaO₃ thin films exhibited highly c-axis orientation under 30 Pa. It was observed by scanning electron microscopy (SEM) that the as-grown film in the optimal conditions was characterized by a dense and homogeneous surface without cracks, and the average grain size was in the order of 25 nm.     

Preparation and characterization of La0.9Sr0.1Ga0.8Mg0.2O3−δ thin film electrolyte deposited by RF magnetron sputtering on the porous anode support for IT-SOFC

Thin films of solid electrolyte La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM) were deposited by RF magnetron sputtering onto porous La_0.7Sr_0.3Cr_0.5Mn_0.5O_3−δ (LSCM) anode substrates. The effects of substrate temperature, sputtering power density and sputtering Ar gas pressure on the LSGM thin film density, flatness and morphology were systematically investigated. RF sputtering power density of 7.8 W cm⁻², substrate temperature of 300 °C and sputtering Ar gas pressure of 5 Pa are identified as the best technical parameters. In addition, a three-electrode half cell configuration was selected to investigate the electrochemical performance of the thin film. The LSGM film deposited at optimum conditions exhibited a lower area specific ohmic resistance of 0.68 Ω cm⁻² at 800 °C, showing that the practicability of RF magnetron sputtering method to fabricate LSGM electrolyte thin film on porous LSCM anode substrates.     

Improved electrical properties of tin-oxide films by using ultralow-pressure sputtering process

The improved structural and electrical properties of tin-oxide films produced by using ultralow-pressure sputtering (ULPS) method are reported. The Hall mobility of the film (~ 13 cm²/V s) deposited using ULPS was about 1.5 times higher than that of the film (~ 8 cm²/V s) sputtered using a pressure of 4.0 × 10^− 1 Pa. As the sputtering pressure was decreased, the film was transformed from an amorphous structure to a nano-crystalline one and gained a stoichiometric SnO₂ composition. These changes in the film structure sufficiently decreased the carrier concentration to facilitate application to thin film transistors.     

in situ Preparation of superconducting HgBa2CuO4 thin films

Superconducting thin films of HgBa₂CuO₄ have been grown in situ by using a sputtering method for the first time. (100) SrTiO₃ was used as substrates and heated between 500 ° C to 600 ° C during the film deposition. By setting the deposition conditions properly, c axis oriented HgBa₂CuO₄ films were grown perpendicularly to the substrate surface. It was found that Hg composition in the deposited films had close relation to the sputtering gas, namely, the oxygen partial pressure, Hg could remain in the film when the partial pressure of oxygen was lower than in the case of the other oxide superconductors such as Bi cuprates. The optimum oxygen partial pressure for the crystallized thin film ranged from 0.1 Pa to 0.01 Pa with total gas pressure of 0.6 Pa. The superconducting transition was observed at around 75K.     

Influence of deposition parameters on preferred orientation of RF magnetron sputtered BST thin films

Ba_0.65Sr_0.35TiO₃ (BST) thin films have been deposited by radio frequency magnetron sputtering. The effects of the deposition parameters on the crystallization and microstructure of BST thin films were investigated by X-ray diffraction and field emission scanning electron microscopy, respectively. The crystallization behavior of these films was apparently affected by the substrate temperature, annealing temperature and sputtering pressure. The as-deposited thin films at room temperature were amorphous. However, the improved crystallization is observed for BST thin films deposited at higher temperature. As the annealing temperature increased, the dominant X-ray diffraction peaks became sharper and more intense. The dominant diffraction peaks increased with the sputtering pressures increasing as the films deposited at 0.37–1.2 Pa. With increasing the sputtering pressure up to 3.9 Pa, BST thin films had the (110) + (200) preferred orientation. Possible correlations of the crystallization with changes in the sputtering pressure were discussed. The SEM morphologies indicated the film was small grains, smooth, and the interface between the film and the substrate was sharp and clear.     

Effects of oxygen pressure on the microstructural,ferroelectric and magnetic properties of BiFe0.95Mn0.05O3 thin films grown on Si substrates

We have investigated the effects of oxygen pressure on the microstructure, leakage current, ferroelectric and magnetic properties of BiFe_0.95Mn_0.05O₃ (BFMO) thin films epitaxially grown on SrRuO₃, SrTiO₃, and TiN-buffered (001)-oriented Si substrates. X-ray diffraction θ?2θ scans and scanning electron microscope images reveal that the epitaxy and microstructures of the BFMO films were strongly dependent on oxygen pressure during film deposition. Epitaxial BFMO films can be obtained in a low oxygen pressure of 2 Pa while polycrystalline BFMO films were obtained in a relatively high oxygen pressure of 15 Pa. Furthermore, the oxygen pressure strongly influences the ferroelectric properties of the BFMO films grown on Si. The remnant polarization (2P _r) of approximately 107 μC/cm² and coercive field (2E _c) of approximately 580 kV/cm were observed for the epitaxial BFMO films grown in a low oxygen pressure of 2 Pa. The saturation magnetization of the BFMO films decreases with increasing oxygen pressure while the magnetic coercive field remains unchanged.     

Preparation of the hard CNx thin films using NO ambient gas by pulsed laser deposition

Pulsed laser deposition (PLD) technique has been widely used in thin film preparation because of its wonderful and excellent properties and amorphous carbon nitride (CN_x) thin films are recognized to have potential for applications like hard coating and electron field emission device. We have deposited CN_x thin films by KrF excimer laser – (λ= 248 nm) ablation of pure graphite target in pure NO gas ambient condition. In this paper, we have prepared the CN_x thin films at various ambient NO gas pressure of 1.3–26 Pa and laser fluence of 2– 5J cm^?2 on Si (100) substrate. We consider that the hardness of CN_x thin films improves due to the increase the nitrogen/carbon (N/C) ratio. The N/C ratio depended on the ambient NO gas pressure and laser fluence. We obtainedthe maximum N/C ratio of 1.0 at NO 3.3 Pa. The typical absorption of CN bonds such as sp² C–N, sp³ C–N, G band and D band were detected from the infrared absorption measurement by FTIR in the deposited CN_x thin films.     

Effect of vacuum annealing on the phase composition of In/SnO/Si, In/SnO2/Si, and Sn/In2O3/Si heterostructures

The chemical interaction between indium and thin SnO and SnO₂ films and between tin and thin In₂O₃ films during vacuum annealing was studied. The metallic films were deposited onto single-crystal silicon substrates by magnetron sputtering, the SnO and SnO₂ films were produced by heat-treating the Sn film in flowing oxygen at 673 and 873 K, respectively, and the In₂O₃ film was produced by heat-treating the In film at 573 K. The results indicate that annealing of the In/SnO/Si and In/SnO₂/Si heterostructures in vacuum (residual pressure of 0.33 × 10^?2 Pa) at 773 K gives rise to the reduction of Sn and oxidation of In, whereas annealing of Sn/In₂O₃/Si causes partial tin substitution for indium in the cubic indium oxide lattice.     

Deposition of c-axis orientation aluminum nitride films on flexible polymer substrates by reactive direct-current magnetron sputtering

Aluminum nitride (AlN) piezoelectric thin films with c-axis crystal orientation on polymer substrates can potentially be used for development of flexible electronics and lab-on-chip systems. In this study, we investigated the effects of deposition parameters on the crystal structure of AlN thin films on polymer substrates deposited by reactive direct-current magnetron sputtering. The results show that low sputtering pressure as well as optimized N₂/Ar flow ratio and sputtering power is beneficial for AlN (002) orientation and can produce a highly (002) oriented columnar structure on polymer substrates. High sputtering power and low N₂/Ar flow ratio increase the deposition rate. In addition, the thickness of Al underlayer also has a strong influence on the film crystallography. The optimal deposition parameters in our experiments are: deposition pressure 0.38 Pa, N₂/Ar flow ratio 2:3, sputtering power 414 W, and thickness of Al underlayer less than 100 nm.