Scanning microwave impedance microscopy (sMIM) is an emerging technique that can provide detailed information beyond that of conventional scanning capacitance microscopy (SCM), and other electrical scanning probe microscopy (SPM) techniques, for the investigation and failure analysis (FA) of semiconductor devices. Integration of new dielectric materials at lower levels of the device structure with the need for quantification of dielectric and dopants in semiconductor devices with sub-micron spatial resolution pushes the practical boundaries of typical atomic force microscopy (AFM) electrical modes. sMIM can measure both linear and non-linear materials (insulators and doped semiconductors, respectively) simultaneously. sMIM has a linear response to log k (dielectric number) and log N (doping concentration) making it an ideal method for providing quantitative measurements of semiconductor devices over a large range of values. This work demonstrates an example of a practical application of sMIM for quantitative measurement of the dopant concentration profile in production semiconductor devices. A planar dopant calibration sample is used to calibrate the sMIM prior to performing the measurements on an “unknown” production device. We utilize nanoscale C-V data to establish a calibration curve for both n- and p-type carriers and apply the calibration curve to an “unknown” device, presenting the measurements in units of doping concentration.

Thermal insulation performance is a measurement of the thermal protection offered by the thermal barrier coatings (TBCs) to the substrate, therefore, it is essentially important to compare different double ceramic layer (DCL) TBCs on the premise of the same thermal resistance. In this study, a series of LZO/YSZ DCL-TBCs, with the equivalent thermal insulation to 500 µm thick YSZ TBCs, were prepared, and their lifetimes were evaluated by thermal gradient cyclic test at the top coat surface temperature of 1300°C. Result show that, the lifetime of DCL-TBCs was more than doubled compared to 500 µm thick YSZ TBCs, when 100µm thick YSZ coating was substituted by LZO coating. In addition, the lifetime of DCL-TBCs decreased with the increase of LZO substitutional ratio. X-ray diffraction analysis revealed that LZO maintains the pyrochlore structure after thermal cyclic test. Microstructure examination demonstrated that, with the increase of LZO substitutional ratio, the delamination position transferred from near top/bond coating interface to near LZO/YSZ interface and finally to the inside of LZO coating. Therefore, this study would shed light to further coating structure optimization towards the next generation advanced DCL-TBCs.

The non-parabolic isothermal oxidation kinetics of low pressure plasma sprayed MCrAlY bond coat was investigated. To qualitatively explain the abnormal growth phenomenon of thermally grown oxides (TGO), the changes that occurred to their microstructure during the oxidation process were studied. Based on these observations, a modified model was developed to understand and quantitatively predict the non-parabolic oxidation and growth kinetics of TGO. This modified model, which fits well with experimental results, provides a novel method to quantitatively predict the long-term growth behaviour of TGO, and thereby benefits the development of long-life and highly reliable thermal barrier coatings.

B 4 C-Ni powders ranging in content from 5-60 wt% Ni were fabricated by pressurized hydrogen reduction and deposited on mild carbon steel substrates by air plasma spraying. The microstructure, morphology, and phase composition of the powders and coatings were evaluated by means of SEM and XRD analysis. The influence of Ni content on coating microstructure, fretting wear resistance, hardness, and adhesive strength was investigated in detail. The results show that Ni affects fretting wear resistance, which was found to be highest in the coating with 40 wt% nickel. The B 4 C-40Ni coating also proved superior in terms hardness, porosity, and friction coefficient, although its adhesive strength was the lowest.

Transparent hydrophobic materials have broad application prospects in industry and daily life due to its transparent and super-hydrophobic characteristics, while its performance will be significantly influenced by the materials and its surface morphology. Hydrophobicity and transparency are competitive properties from the viewpoint of surface roughness. However, there are still a lot of problems to be solved to satisfy hydrophobicity and transparency simultaneously in the prepared surface. A novel and simple method to fabricate transparent hydrophobic surface is introduced in the present paper. Micron and sub-micron mixed Al 2 O 3 powders were deposited on the glass and plastic substrate by vacuum cold spray. The coatings were modified by 1,1,2,2- Tetrahydroperfluorodecyltrimethoxysilane (FAS) to reduce the surface energy. The surface morphology was characterized by scanning electron microscopy (SEM) and 3D laser microscopy (LSM). The transmittance of the coating was also investigated. The results show that the as-sprayed surfaces exhibit submicron structure. After FAS absorbing treatment, the contact angle of water droplets on the coatings ranged from 108° to 136° depending on the local surface morphology, and the transmittance of Al 2 O 3 coatings are all above 80% in the range of visible light.

A new method to fabricate micro-nano scaled surface with super-hydrophobicity is introduced in the present paper. Micro-nano hierarchical structure coatings based on silica (SiO 2 ) micron particles were successfully deposited on the stainless steel substrates by high-velocity oxygen fuel (HVOF) spraying which were modified by 1,1,2,2- Tetrahydroperfluorodecyltrimethoxysilane (FAS) to reduce surface energy. The influences of the HVOF process parameters on the wettability of the coatings were investigated. The coatings were characterized by scanning electron microscopy (SEM), 3D laser microscopy (LSM), and Fourier transform infrared spectrometer (FTIR). The results show that the as-sprayed surfaces exhibit micro-nano hierarchical structure. The water droplets are strongly adhesive to the as-sprayed surface, while by FAS absorbing treatment, the surfaces exhibit super-hydrophobicity, whose contact angle with water droplets are as high as 150°, and the water droplets tend to roll on the surface with extremely low adhesion with a sliding angle of 3°

Thermally grown oxide (TGO) that naturally forms on bond coat surfaces plays an important role in determining the lifetime of thermal barrier coatings (TBCs). Splashed particles on thermally sprayed MCrAlY bond coat surfaces are weakly bonded to the underlying bulk coating, leading to the formation of mixed oxides that contribute to TBC failure. In this study, various heat treatments are used to modify the weakly bonded splashed particles on LPPS CoNiCrAlY bond coats in order to restrain the formation of mixed oxides and prevent associated failures.

In this paper, the application of scanning near-field photon emission microscopy for imaging photon emission sites is demonstrated. Photon emissions generated by a Fin-FET test structure with one metallization layer are imaged with spatial resolution of 50 nm using scattering dialectic probe. The potential applications and limitations of the technique are discussed.

Cavitation erosion is one of the major problems of hydraulic machinery and may cause the equipment to reduce power and then to stop working. Now with the study of nanomaterials, some special properties of nanostructured coatings are recognized and HVOF nanostructured WC-12Co coating may possess far more excellent potential to protect equipment from cavitation erosion than the conventional HVOF coatings. In the present paper nanostructured and conventional coatings were deposited by HVOF. Resistance of the coatings to cavitation erosion was studied by ultrasonic vibration cavitation equipment. Cavitation pits and craters were observed by SEM and cavitation mechanisms were explored. The results showed that nanostructured coating demonstrated more excellent performance in cavitation erosion and the erosion rate is approximately one third that of conventional one. The nanostructured existence and the increase in microhardness and toughness of the coating are important factors, which influence the resistance of coatings to cavitation erosion.

In the present paper, nanostructured, multimodal and conventional WC-12Co cermet coatings were deposited by HVOF and the properties and structures of the coatings such as microhardness, microstructure, phase composition and wear resistance were compared. Finally the wear failure mechanisms of WC-12Co coatings were explored by XRD and SEM analysis. Research results show that microstructures of nanostructured and multimodal WC-12Co coatings deposited by HVOF are dense with little porosity, and their microhardness values are obviously higher than conventional WC-12Co coating. As well, it was found that nanostructured and multimodal WC-12Co coatings exhibited better erosion and adhesive wear resistance in comparison with conventional coating, and nanostructured WC-12Co coatings possessed the best erosion resistance properties at large impact angles and adhesive wear resistance. At small impact angles, WC-12Co coatings deposited by HVOF demonstrate better erosion wear resistance than at large impact angles and the erosion wear performance at 30º is more than 1.7 times higher than at 90º. In comparison with conventional WC-12Co HVOF sprayed coating, the adhesive wear resistance of the nanostructured and multimodal coatings is respectively enhanced by above 70% and 50%. Testing results also show that although decarburization of WC occurred during spraying multimodal and nanostructured WC-12Co powders, the decarburization of WC for the nanostructured powder was more severe.

Iron base composite coatings were deposited on mild steel substrates by arc spraying and cored wire with TiC ceramic powders. The abrasive wear resistance properties were examined on the MLS-225 wet sand/rubber wheel tester. The microstructure, phase compositions and worn surface morphologies of the coatings were observed by means of optical, scanning electron microscopy and X-ray diffraction. The results showed that composite coatings with TiC ceramic hard phases were reinforced by the TiC hard particles distributed in the iron-based coating. The average micro hardness of the coatings is about 1137 HV0.1. The coatings have the excellent abrasive wear resistance which is 6 times higher than that of the Q235 mild steel. Wear mechanisms of coatings was mainly micro-ploughing and brittle fracture.

The three typical TEM specimen preparation methods are investigated for two different ultra-thin gate dielectric materials analysis. The results show that the mechanical polishing with short time, low angle ion milling is best specimen preparation method for both samples. FIB finial thinning can be used for SiON gate dielectric specimen analysis, but is not suitable for HfO2 gate dielectric analysis. After FIB thinning, severe Ga and Pt contamination on the specimen surface is found when using HR-STEM/HAADF imaging.

Spinel soft ferrites such as NiZnFe 2 O 4 are of great interest due to their extensive applications in magnetic-optics, microelectronics, and microwave devices. This study deals with the production of thick Ni 0.5 Zn 0.5 Fe 2 O 4 magnetic films (>50 microns) using high velocity oxy-fuel (“HVOF”) thermal spray. With the HVOF process, high density films more than 98% theoretical density were prepared, apparently due to the high velocity of droplets in the process. The influence of the fuel composition on coating structure, deposition efficiency, and magnetic properties of the Ni-Zn ferrite films was investigated. Better magnetic properties were obtained in the as-sprayed film formed with a neutral or oxygen-rich flame. The decomposition of the ferrite material occurred with a fuel-rich flame and resulted in a reduction in magnetic properties. However, the magnetic properties could be improved dramatically after heat treatment. Pellet and toroid samples of these films were produced for evaluation of magnetic properties by saturation magnetization and magnetic permeability. The permeability exhibited a very flat response to high frequencies up to 13 MHz.