Low temperature ordering of FePt films by in-situ heating deposition plus post deposition annealing

FePt thin films with 40 nm thickness were prepared on thermally oxidized Si (001) substrates by dc magnetron sputtering at the nominal growth temperature 375 °C. The effects of annealing on microstructure and magnetic properties of FePt thin films were investigated. The as-deposited FePt thin films show soft magnetic properties. After the as-deposited FePt thin films were annealed at various temperatures and furnace cooled, it is found that the ordering temperature of L1₀ FePt phase could be reduced to 350 °C. For FePt thin films annealed at 350 °C, the in-plane and out-of-plane coercivities of the films increased to 510 and 543 kA/m, respectively, and the films had hard magnetic properties. A highly (001) orientation was obtained, when FePt thin films were annealed at 600 °C. And the hysteresis loops of FePt thin films annealed at 600 °C show out-of-plane magnetic anisotropy.     

Fe<Subscript>73.5</Subscript>Cu<Subscript>1</Subscript>Nb<Subscript>3</Subscript>Si<Subscript>15.5</Subscript>B<Subscript>7</Subscript> Thin Films Deposited by HiPIMS: Magnetic and Magnetostrictive Behavior

Results concerning the magnetic, magnetostrictive, structural, morphological, and topological properties of amorphous and nanocrystalline Fe _73.5Cu ₁Nb ₃Si _15.5 B ₇ thin films deposited using the high power impulse magnetron sputtering (HiPIMS) technique are reported. In as-deposited state, the samples are amorphous, the nanocrystalline state being achieved for samples isothermally annealed at adequate temperatures, in an electric furnace. For the optimum annealing temperature (475 ^°C), a decrease by about 70 % for the coercive magnetic field (50 A/m) and up to 1 order of magnitude for the saturation magnetostriction (~1×10^?6), compared to the as-deposited state, was obtained. The X-ray diffractometry (XRD) and scanning electron microscopy (SEM) results for samples thermally treated at 475 ^°C revealed a 53.6 % crystalline volume fraction of α-Fe(Si) nanograins with an average size of about 15 nm and a Si content of 10.78 %, uniformly dispersed in a residual amorphous matrix. Using the saturation magnetostriction values determined using the cantilever deflection method and the crystalline volume fraction of α-Fe(Si) nanograins, the contribution of crystalline phase to the saturation magnetostriction was also determined.     

Magnetic properties of NiFe2O4 thin films grown on La0.7Sr0.3MnO3-buffered Si substrate

Nickel ferrite NiFe₂O₄ (NFO) thin films have been prepared on a Si substrate (NFO/Si) and La_0.7Sr_0.3MnO₃ (LSMO)-coated Si (100) substrate (NFO/LSMO/Si) by RF magnetron sputtering. The microstructures and magnetic properties of the two films were systematically investigated. X-ray diffraction (XRD) and atomic force microscopy (AFM) revealed that highly (331)-oriented NFO films with a smooth surface were grown on the LSMO/Si substrate. The magnetization of the films was measured at room temperature. It showed a clear hysteresis loop in both samples, with the magnetic field applied in the plane. However, no hysteresis loop is seen with the magnetic field applied perpendicular to the film plane. This indicates the presence of an anisotropy favoring the orientation of the magnetization in the direction parallel to the film plane. A study of magnetization hysteresis loop measurements indicates that the LSMO buffer layer may improve the magnetic properties of NFO thin films, and that the saturation magnetization increases from 4.15 × 10⁴ to 3.5 × 10⁵ A/m.     

Effect of growth temperature on structural, electrical and optical properties of dual ion beam sputtered ZnO thin films

ZnO epitaxial thin films were grown on p-type Si(100) substrates by dual ion beam sputtering deposition system. The crystalline quality, surface morphology, optical and electrical properties of as-deposited ZnO thin films at different growth temperatures were studied. Substrate temperature was varied from 100 to 600 °C at constant oxygen percentage O₂/(O₂ + Ar) % of 66.67 % in a mixed gas of Ar and O₂ with constant chamber pressure of 2.75 × 10^?4 mBar. X-Ray diffraction analyses revealed that all the films had (002) preferred orientation. The minimum value of stress was reported to be ?0.32 × 10¹⁰ dyne/cm² from ZnO film grown at 200 °C. Photoluminescence measurements demonstrated sharp near-band-edge emission (NBE) was observed at ~375 nm along with deep level emission (DLE) in the visible spectral range at room temperature. The DLE Peak was found to have decrement as ZnO growth temperature was increased from 200 to 600 °C. The minimum FWHM of the NBE peak of 16.76 nm was achieved at 600 °C growth temperature. X-Ray photoelectron spectroscopy study revealed presence of oxygen interstitials and vacancies point defects in ZnO film grown at 400 °C. The ZnO thin film was found to be highly resistive when grown at 100 °C. The ZnO films were found to be n-type conducting with decreasing resistivity on increasing substrate temperature from 200 to 500 °C and again increased for film grown at 600 °C. Based on these studies a correlation between native point defects, optical and electrical properties has been established.     

Electrical properties of boron- and phosphorous-doped microcrystalline silicon thin films prepared by magnetron sputtering of heavily doped silicon targets

The boron(B)- and phosphorous(P)-doped microcrystalline silicon (Si) thin films were prepared by magnetron sputtering of heavily B- and P-doped Si targets followed by rapid thermal annealing (RTA), their electrical properties were characterized by temperature-dependent Hall and resistivity measurements. It was observed that the dark conductivity and carrier concentration of the 260 nm B-doped Si films annealed at 1,100 °C in Ar were 3.4 S cm^?1 and 1.6 × 10¹⁹ cm^?3, respectively, which were about one order of magnitude higher than that of P-doped Si films. The activation energy of the B- and P-doped Si films were determined to be 0.23 eV and 0.79 eV, respectively. The dark conductivity of B- and P-doped Si films increased with the increase of film thickness, RTA temperature, and the incorporation of H₂ in Ar during RTA. The present work provides an easy and non-toxic method for the preparation of doped microcrystalline Si thin films.     

Effect of sputtering power and annealing temperature on the properties of indium tin oxide thin films prepared from radio frequency sputtering using powder target

Indium tin oxide (ITO) thin films were deposited on quartz substrates by radio frequency (RF) sputtering with different RF power (100–250 W) using the powder target at room temperature. The effect of sputtering power on their structural, electrical and optical properties was systematically investigated. The intensity of (400) orientation clearly increases with the sputtering power increases, although the films have (222) preferred orientation. Increasing sputtering power is benefit for lower resistivity and transmittance. The films were annealed at different temperature (500–800 °C), then we explored the relationship between their electro-optical and structural properties and temperature. It has been observed that the annealed films tend to have (400) orientation and then show the lower resistivity and transmittance. The ITO thin film prepared by RF sputtering using powder target at 700 °C annealing temperature and 200 W sputtering power has the resistivity of 2.08 × 10^?4 Ω cm and the transmittance of 83.2 %, which specializes for the transparent conductive layers.     

Study of optoelectronics and microstructures on the AZO/nano-layer metals/AZO sandwich structures

In this study, growth nano-layer metals (Al, Cu, Ag) and Al-doped ZnO (AZO) thin films are deposited on glass substrates as the transparent conducting oxides (TCOs) to form AZO/nano-layer metals/AZO sandwich structures. The conductivity properties of thin films are enhanced when the average transmittance over the wavelengths 400–800 nm is maintained at higher than 80 %. A radio frequency magnetron sputtering system is used to deposit the metal layers and AZO thin films of different thickness, to form AZO/Al/AZO (ALA), AZO/Cu/AZO (ACA) and AZO/Ag/AZO (AGA) structures. X-ray diffraction and field emission scanning electron microscopy are used to analyze the crystal orientation and structural characteristic. The optical transmission and resistivity are measured by UV–VIS–NIR spectroscopy and Hall effect measurement system, respectively. The results show that when the Ag thickness is maintained at approximately 9 nm, the TCOs thin film has the lowest resistivity of 8.9 × 10^?5 Ω-cm and the highest average transmittance of 81 % over the wavelengths 400–800 nm. The crystalline Ag nano-crystal structures are observed by high-resolution transmission electron microscopy. In addition, the best figure of merit for the AZO/Ag/AZO tri-layer film is 2.7 × 10^?2 (Ω^?1), which is much larger than that for other structures.     

N掺杂Cu2O薄膜的低温沉积及快速热退火研究

采用氧化亚铜(Cu_2O)陶瓷靶,利用射频磁控溅射沉积法在氮气和氩气的混合气氛下制备了N掺杂Cu_2O(Cu_2O∶N)薄膜,并在N_2气氛下对薄膜进行了快速热退火处理,研究了N_2流量和退火温度对Cu_2O∶N薄膜的生长行为、物相结构、表面形貌及光电性能的影响。结果显示,在衬底温度300℃、N_2流量12sccm条件下生长的薄膜为纯相Cu_2O薄膜;在N_2气氛下对预沉积薄膜进行快速热退火处理不影响薄膜的物相结构,薄膜的结晶质量随退火温度(450℃)的升高而显著改善;快速热退火处理能改善薄膜的结晶质量和缺陷,降低光生载流子的散射,增强载流子的传输,预沉积Cu_2O∶N薄膜经400℃退火处理后展示出较好的电性能,薄膜的霍尔迁移率(μ)为27.8cm~2·V~(-1)·s~(-1)、电阻率(ρ)为2.47×10~3Ω·cm。研究表明低温溅射沉积和快速热退火处理能有效改善Cu_2O∶N薄膜的光电性能。     

Underlayer dependence of microtexture, microstructure and magnetic properties of c-axis oriented strontium ferrite thin films

Strontium ferrite (SrM) thin films were prepared by dc magnetron sputtering system on thermally oxidized silicon wafer (SiO₂/Si), single-crystal sapphire with (00l) orientation and single-crystal MgO with (111) orientation and the effect of Au and Pt underlayers on morphology and magnetic properties was studied. Experimental results revealed that with the application of underlayers, the crystallization temperature of SrM was reduced. Strontium ferrite thin films with uniaxial anisotropy were formed on all substrate specimens. Comparison of the results obtained on all thin films indicated that the maximum saturation magnetization and coercivity in the perpendicular direction were 0.377 T and 0.382 MAm^− 1, respectively, for thin films with Au underlayer and SiO₂/Si substrate.     

Characterization of aluminum-doped zinc oxide thin films by RF magnetron sputtering at different substrate temperature and sputtering power

In this study, transparent conductive Al doped zinc oxide (ZnO: Al, AZO) thin films with a thickness of 40 nm were prepared on the Corning glass substrate by radio frequency magnetron sputtering. The properties of the AZO thin films are investigated at different substrate temperatures (from 27 to 150 °C) and sputtering power (from 150 to 250 W). The structural, optical and electrical properties of the AZO thin films were investigated. The optical transmittance of about 78 % (at 415 nm)–92.5 % (at 630 nm) in the visible range and the electrical resistivity of 7 × 10^?4 Ω-cm (175.2 Ω/sq) were obtained at sputtering power of 250 W and substrate temperature of 70 °C. The observed property of the AZO thin films is suitable for transparent conductive electrode applications.     

Effect of film thickness on properties of aluminum doped zinc oxide thin films deposition on polymer substrate

A series of aluminum doped zinc oxide thin films with different thickness (25–150 nm) were deposited on indium tin oxide coated polyethylene terephthalate substrates by radio frequency magnetron sputtering method at room temperature. The structural, optical and electrical properties of the films were investigated by X-ray Diffractometer, UV–Vis spectrometer and Hall Effect Measurement System. All the obtained films were polycrystalline with a hexagonal structure and a preferred orientation along [002] direction with the c-axis perpendicular to the substrate surface. The optical energy band gap (E_g) values of the films were found to be in the range from 3.36 to 3.26 eV, and their average optical transmissions were about 75 % in the visible region. The films had excellent electrical properties with the resistivities in the range from 2.78 × 10^?5 to 2.03 × 10^?4 Ω cm, carrier densities more than 3.35 × 10²¹ cm^?3 and Hall mobilities between 5.77 and 11.13 cm²/V s.     

退火处理对TiO2薄膜结构和透射的影响

在常温下,采用射频反应磁控溅射方法在不同溅射功率下于K9双面抛光玻璃基底上制备二氧化钛薄膜.将制备的样品进行450℃退火6h热处理.利用X射线衍射仪(XRD)对比分析了退火前后薄膜的微观结构,采用光栅光谱仪测试了退火前后薄膜样品的透射谱.实验结果表明,退火前薄膜样品是非晶态,退火后薄膜晶化为晶态,但不同溅射功率下制备的薄膜结晶取向有差异;退火热处理对薄膜的折射率有一定影响,表现为退火前后透射谱偏移.     

The influences of rapid-thermal annealing on the characteristics of Sr0.6Ba0.4Nb2O6 thin film

The Sr0.6Ba0.4Nb2O6 (SBN) thin films were successfully prepared on Pt/Ti/Si and SiO2/Si/Al substrates and crystallized subsequently using rapid thermal annealing (RTA) process in ambient atmosphere for 1 min. The surface morphologies and thicknesses of as-deposited and annealed SBN thin films were characterized by field emission scanning electron microscopy, and the thickness was about 246 nm. As compared with the as-deposited SBN thin films, the RTA-treated process had improved the crystalline structures and also had large influence on the crystalline orientation. When the annealing temperatures increased from 700 degrees C to 900 degrees C, the diffraction intensities of (410) and (001) peaks apparently increased. Annealed at 900 degrees C, the (001) peak had the maximum texture coefficient and SBN thin films showed a highly c-axis (001) orientation. The influences of different RTA-treated temperatures on the polarization-applied electric field (P-E) curves and the capacitance-voltage (C-V) curves were also investigated.     

Study of FePt films prepared by reactive sputtering

In the present study, ⁵⁷FePt films are prepared with reactive ion beam sputtering using mixture of argon and nitrogen gases. Energy-dispersive X-ray reflectivity is used to estimate the thickness of the as-deposited films. Structural and magnetic properties of the as-deposited and annealed films are studied using grazing incidence X-ray diffraction (GIXRD), magneto-optical Kerr effect (MOKE) and conversion electron Mossbauer spectroscopy (CEMS). Significant difference in structural and magnetic properties i.e., formation of ordered L1₀ phase and perpendicular magnetic anisotropy are observed for the films prepared with mixture of nitrogen and argon as compared to the film prepared with argon only. From the GIXRD, peaks corresponding to the ordered face-centred tetragonal FePt phase are observed for the films prepared with mixture gas. The results of CEMS clearly show the perpendicular magnetic anisotropy (PMA) for the films prepared with mixture of nitrogen and argon. The observed enhanced chemical ordering and the development of PMA in the films prepared with mixture gas is due to the role played by the defects created as a consequence of nitrogen escape in the films with high temperature annealing.     

Effect of substrate temperature on properties of Cu(In,Ga, Al)Se<Subscript>2</Subscript> films grown by magnetron sputtering

Cu(In, Ga, Al)Se₂ (CIGAS) thin films were deposited by magnetron sputtering on Si(100) and soda-lime glass substrates at different substrate temperatures, followed by post-deposition annealing at 350 or 520 °C for 5 h in vacuum. Electron probe micro-analysis and secondary ion mass spectroscopy were used to determine the composition of the films and the distribution of Al across the film thickness, respectively. X-ray diffraction analysis showed that the (112) peak of CIGAS films shifts to higher 2θ values with increasing substrate temperature but remains unchanged when the films were annealed at 520 °C for 5 h. Scanning electron microscopy and atomic force microscopy images revealed dense and well-defined grains for both as-deposited and annealed films. However, notable increase in grain size and roughness was observed for films deposited at 500 °C. The bandgap of CIGAS films was determined from the optical transmittance and reflectance spectra and was found to increase as the substrate temperature was increased.     

直流磁控反应溅射制备IrO2薄膜

为研究氧化铱（ＩｒＯ２）对ＰＺＴ铁电薄膜疲性能的影响。利用直流（ＤＣ）磁控反应溅射（ｓｐｕｔｔｅｒｉｎｇ）工艺成功地在ＳｉＯ２／Ｓｉ（１００）衬底上制得了高度取向的ＩｒＯ２薄膜,并在其上制成ＰＺＴ铁电薄膜,讨论了溅射参数（溅射功率、Ａｒ／Ｏ２比、衬底温度）以及退火条件对氧化铱薄膜的结晶,取向和形态的影响。     

Structural,electrical, optical properties and reliability of ultra-thin tin doped indium oxide films for touch panels

Ultra-thin ITO films with thickness of 4–56 nm were deposited on glass by dc magnetron sputtering using 5 wt% SnO₂ doped ITO target. The effect of film thickness on the structural, electrical, optical properties and reliability was investigated for its application to touch panels. The 4 nm thick ITO film shows amorphous structure and other films present polycrystalline structure and the (222) preferred orientation. The ultra-thin ITO films show smooth surface with low Ra surface roughness smaller than 1 nm. The sheet resistance and visible transmittance of the ITO films decrease with the increase in film thickness. The 4 nm thick ITO film shows the highest resistivity (3.08 × 10^?3 Ω cm) with low carrier density and Hall mobility, and other films have excellent conductivity (<4.0 × 10^?4 Ω cm). The ITO films show high transmittance (>85 %) in visible light range and do not generate interference ripples between film and substrate interface. The ITO films with thickness of 18–56 nm show stable reliability under high temperature, high temperature & high humidity and alkaline environmental conditions. The only electrical degradation corresponds to the increase of sheet resistance in the ITO films with thickness of 4–12 nm.     

Fabrications of SnS thin films and SnS-based heterojunctions on flexible polyimide substrates

The flexible polyimide substrates were utilized to realize the flexibility of SnS thin films and SnS-based heterojunctions. The SnS thin films and ZnO/SnS heterojunctions were deposited on polyimide substrates by magnetron sputtering. The properties of SnS thin films and ZnO/SnS heterojunctions were studied. The experimental results show that the post annealing can enhance the degree of crystallinity of flexible SnS thin films. The annealed SnS thin films present polycrystalline structure with preferential orientation along the (040) plane and grain size of 18 nm. The compositions of as-deposited and annealed flexible SnS thin films are close to the stoichiometry of SnS. The direct band gaps are 1.48 and 1.32 eV for the as-deposited and annealed SnS thin films, respectively. The fabricated flexible ZnO/SnS heterojunctions show rectifying properties with the rectifying ratio of 6.85 and the diode ideal factor of 1.23. The experimental results indicate the feasibility of using polyimide as the substrates of SnS thin films and SnS-based heterojunctions.     

Magnetic properties of NiFe2O4 thin films grown on La0.7Sr0.3MnO3-buffered Si substrate

Nickel ferrite NiFe₂O₄ (NFO) thin films have been prepared on a Si substrate (NFO/Si) and La_0.7Sr_0.3MnO₃ (LSMO)-coated Si (100) substrate (NFO/LSMO/Si) by RF magnetron sputtering. The microstructures and magnetic properties of the two films were systematically investigated. X-ray diffraction (XRD) and atomic force microscopy (AFM) revealed that highly (331)-oriented NFO films with a smooth surface were grown on the LSMO/Si substrate. The magnetization of the films was measured at room temperature. It showed a clear hysteresis loop in both samples, with the magnetic field applied in the plane. However, no hysteresis loop is seen with the magnetic field applied perpendicular to the film plane. This indicates the presence of an anisotropy favoring the orientation of the magnetization in the direction parallel to the film plane. A study of magnetization hysteresis loop measurements indicates that the LSMO buffer layer may improve the magnetic properties of NFO thin films, and that the saturation magnetization increases from 4.15 × 10⁴ to 3.5 × 10⁵ A/m.     

Growth of CZTS thin films by sulfurization of sputtered single-layered Cu–Zn–Sn metallic precursors from an alloy target

Cu₂ZnSnS₄ (CZTS) thin films were prepared by sulfurizing single-layered metallic Cu–Zn–Sn precursors which were deposited by DC magnetron sputtering using a Cu–Zn–Sn ternary alloy target. The composition, microstructure and properties of the CZTS thin films prepared under different sputtering pressure and DC power were investigated. The results showed that the sputtering rate of Cu atom increases as the sputtering pressure and DC power increased. The microstructure of CZTS thin films can be optimized by sputtering pressure and DC power. The CZTS thin film prepared under 1 Pa and 30 W showed a pure Kesterite phase and a dense micro-structure. The direct optical band gap of this CZTS thin film was calculated as 1.49 eV with a high optical absorption coefficient over 10⁴ cm^?1. The Hall measurement showed the film is a p-type semiconductor with a resistivity of 1.06 Ω cm, a carrier concentration of 7.904 × 10¹⁷ cm^?3 and a mobility of 7.47 cm² Vs^?1.