Numerous techniques have been used to improve the voltage handling capability of high voltage power devices with the aim to obtain the breakdown of a plane junction. In this work, a new concept of low cost, low surface and high efficiency junction termination for power devices is presented and experimentally validated. This termination is based on a large and deep trench filled by BCB (BenzoCycloButene) associated to a field plate. Simulation results show the important impact of trench design and field plate width on termination performances. The experimental breakdown voltage of this Deep Trench Termination (DT2) is close to 1300 Volts: this value validates not only the concept of the DT2 but also the choice of the BCB as a good dielectric material for this termination.

A new method (VHR method) has been derived from Johnson-Mehl-Avrami (JMA) transformation rate equation to calculate the crystallization kinetic parameters of a glassy system. These parameters include the activation energy of crystallization E (kJ/mol), the kinetic exponent n and the frequency factor Ko (s-1). The VHR method starts with obtaining E. Let us consider xi(t) as the volume fractions of crystallization which are obtained at various heating rates βi (K/min). The method for obtaining E depends on finding the temperatures Ti (K) and the times ti (s) which are required to produce the same values of xi(t) at various values of βi. Next, the value of n is obtained by using the temperatures T1 (K) and T2 (K) and the times t1 (s) and t2 (s) which are extracted at two different values of the volume fraction x1(t) and x2(t) at the same heating rate. Finally, the value of Ko may be obtained at any value of x(t) after obtaining the values of E and n, successively. The applicability and the full descriptions of the VHR method have been thoroughly tested on computer simulated crystallization curves. Also,the validity ofthe VHR method has been checked in the cases of n being temperature-independent and temperature-dependent parameter. The VHR technique has been used to estimate the crystallization parameters of Se75.5Te20Sb4.5 chalcogenide glass under non-isothermal conditions.

A new method (VHR method) has been derived from Johnson-Mehl-Avrami (JMA) transformation rate equation to calculate the crystallization kinetic parameters of a glassy system. These parameters include the activation energy of crystallization E (kJ/mol), the kinetic exponent n and the frequency factor Ko (s-1). The VHR method starts with obtaining E. Let us consider xi(t) as the volume fractions of crystallization which are obtained at various heating rates βi (K/min). The method for obtaining E depends on finding the temperatures Ti (K) and the times ti (s) which are required to produce the same values of xi(t) at various values of βi. Next, the value of n is obtained by using the temperatures T1 (K) and T2 (K) and the times t1 (s) and t2 (s) which are extracted at two different values of the volume fraction x1(t) and x2(t) at the same heating rate. Finally, the value of Ko may be obtained at any value of x(t) after obtaining the values of E and n, successively. The applicability and the full descriptions of the VHR method have been thoroughly tested on computer simulated crystallization curves. Also,the validity ofthe VHR method has been checked in the cases of n being temperature-independent and temperature-dependent parameter. The VHR technique has been used to estimate the crystallization parameters of Se75.5Te20Sb4.5 chalcogenide glass under non-isothermal conditions.

A reliable factorial experimental design was applied to DRIE for specifically producing high-aspect ratio trenches. These trenches are to be used in power electronics applications such as active devices: deep trench superjunction MOSFET (DT-SJMOSFET) and passive devices: 3D integrated capacitors. Analytical expressions of the silicon etch rate, the verticality of the profiles, the selectivity of the mask and the critical loss dimension were extracted versus the process parameters. The influence of oxygen in the passivation plasma step was observed and explained. Finally, the analytical expressions were applied to the devices objectives. A perfectly vertical trench 100-μm deep was obtained for DT-SJMOSFET. Optimum conditions for reaching high-aspect ratio structures were determined in the case of high-density 3D capacitors.

Different thickness of cadmium telluride (CdTe) thin films was deposited onto glass substrates by the thermal evaporation technique. Their structural characteristics were studied by X-ray diffraction (XRD). The XRD experiments showed that the films are polycrystalline and have a zinc-blende (cubic) structure. The microstructure parameters, crystallite size and microstrain were calculated. It is observed that the crystallite size increases and microstrain decreases with the increase in the film thickness. The fundamental optical parameters like band gap and extinction coefficient are calculated in the strong absorption region of transmittance and reflectance spectrum. The possible optical transition in these films is found to be allowed direct transition with energy gap increase from 1.481 to 1.533 eV with the increase in the film thickness. It was found that the optical band gap increases with the increase in thickness. The refractive indices have been evaluated in transparent region in terms of envelope method, which has been suggested by Swanepoul in the transparent region. The refractive index can be extrapolated by Cauchy dispersion relationship over the whole spectral range, which extended from 400 to 2500 nm. It is observed that the refractive index, n increases on increasing the film thickness up to 671 nm and then the variation of n with higher thickness lie within the experimental errors.

Nickel oxide nanoparticles are formed by chemical precipitation and subsequent drying and calcinations at temperatures ≥523 K. Samples are characterized using X-ray diffraction and BET surface area measurements indicating the formation of a single NiO phase whose crystallite size increases with increasing calcination temperature. The electrical properties are examined by measuring DC and AC conductivities and dielectric properties as functions of temperature. Electrical conductivities first slightly increases with increasing particle size up to 7–10 nm and are about 8 orders of magnitude higher than that of NiO single crystals. Further increasing the particle size above 10 nm, leads to a monotonic decrease of conductivity. The data are discussed in view of variations of grain boundary as well as triple junction volume fractions as the particle size varies. At temperatures above θD/2 (θD is the Debye temperature), the conductivity is ascribed to a band-like conduction due to the large polaron. The activation energy of conduction was found to be minimal for the highly conducting samples of 7–10 nm, and gradually increases to ~0.5 eV with increasing the particle size above 10 nm. For T < θD/2, the conductivity is best described by variable–range–hopping models. Model parameters are thus estimated and presented as functions of particle size. Frequency as well as temperature dependencies of the AC conductivity and dielectric constant exhibit trends usually observed in carrier dominated dielectrics.

In this article, we report on the formation of a photocatalytic porphyrin crystalline structure using two oppositely charged commercially available low cost porphyrins, [meso-tetra(N-methy-4-pyridyl)porphyrin tetratosylate (TMPyP) and zinc-tetrakis(4-sulfonatophenyl)porphyrin (Zn-TPPS)], by self-assembly at room temperature without acidification. Using optical microscopy, the crystals were determined to have a length of 30–55 μm and width of 2–50 μm, depending on the molar ratio of the porphyrins in the starting solution. The porphyrin crystals were characterized by means of powder X-ray diffraction and UV–Vis, fluorescence, and optical microscopic techniques. The UV–Vis absorbance spectrum of the crystalline structure is different than those of the monomer solutions, involving a broadened Soret band that is split into two blue-shifted and red-shifted peaks and broadened red-shifted Q-bands. The crystals exhibit a different emission spectrum from those of the porphyrin solutions in that they are red-shifted, split, and show a dramatic decrease in intensities. A hypothetical model for the crystal structure of the porphyrin crystals is developed. Illumination of the crystals in a 2,4,6-trinitrotoluene solution with a tungsten lamp results in TNT reduction to 1,3,5-trinitrobenzene and 4-amino-2,6-dinitrotoluene

Indium tin oxide (ITO) thin film is one of the most widely used as transparent conductive electrodes in all forms of flat panel display (FPD) and microelectronic devices. Suspension of already crystalline conductive ITO nanoparticles fully dispersed in alcohol was spun, after modifying with coupling agent, on glass substrates. The low cost, simple and versatile traditional photolithography process without complication of the photoresist layer was used for patterning ITO films. Using of UV light irradiation through mask and direct UV laser beam writing resulted in an accurate linear, sharp edge and very smooth patterns. Irradiated ITO film showed a high transparency ( 85%) in the visible region. The electrical sheet resistance decrease with increasing time of exposure to UV light and UV laser. Only 5 min UV light irradiation is enough to decrease the electrical sheet resistance down to 5 kΩ

Indium tin oxide (ITO) thin film is one of the most widely used as transparent conductive electrodes in all forms of flat panel display (FPD) and microelectronic devices. Suspension of already crystalline conductive ITO nanoparticles fully dispersed in alcohol was spun, after modifying with coupling agent, on glass substrates. The low cost, simple and versatile traditional photolithography process without complication of the photoresist layer was used for patterning ITO films. Using of UV light irradiation through mask and direct UV laser beam writing resulted in an accurate linear, sharp edge and very smooth patterns. Irradiated ITO film showed a high transparency ( 85%) in the visible region. The electrical sheet resistance decrease with increasing time of exposure to UV light and UV laser. Only 5 min UV light irradiation is enough to decrease the electrical sheet resistance down to 5 kΩ

The pre-crystallization kinetics of Pb10Se90 glass was determined under non-isothermal conditions using a differential scanning calorimetry (DSC) technique. Two isoconversional methods, the Kissinger-Akahire-Sunose and Vyazovkin methods, were used to determine the variation of the activation energy for glass transition with temperature. The results show that only one (three-dimensional growth) mechanism is working simultaneously during the amorphous-glass process of the investigated glass.