Papers by Keyword: Electrical Characteristics

Abstract: A body diode is commonly employed as a free-wheeling diode to reduce costs of SiC components instead of an external Schottky barrier diode. However, one of the key issues is higher reverse recovery loss due to bipolar charge contribution to reverse recovery charge. In this study, we investigated the impact of high-temperature annealing on the characteristics of MOSFETs as a cost-effective approach to introduce minority carrier lifetime killers. The trap densities of Z_1/2 center and EH_6/7 center can be controlled by activation annealing temperature. Q_rr of 1900°C measured at 150°C was significantly decrease by 67% compared to that of 1750°C attributed to the 89% suppression of Q_BIP. However, reverse leakage current increased adversely with the activation annealing temperature. R_on and V_th increased with the activation annealing temperature. The trade-off of the annealing temperature worsened slightly compared to that of the doping concentration. It is still possible that high-temperature annealing represents a cost-effective approach to improve the reverse recovery characteristics of the body diode.

Abstract: A typical Nebulizer Spray Pyrolysis (NSP) technology was used to produce and deposit CuO nanoparticles on glass substrates. In this work, the effects of different precursor volumes on the properties of CuO thin films produced by Nebulizer Spray Pyrolysis (NSP) were investigated. In this work, CuO thin films have been developed using the NSP approach with three different precursor quantities (3, 4, and 5 ml). A monoclinic crystal structure was found using X-ray diffractometry (XRD), which was confirmed to be consistent with JCPDS card No. (89-5899). The XRD studies have been used to calculate the dislocation density, micro strain, and crystallite size. The average thickness was measured using a surface profilometer. High-resolution Schottky emitter FE-SEM has been used to study morphological properties, and the results demonstrate that each film has been evenly deposited on the glass substrate. The presence of the element in the CuO thin films has been confirmed by energy dispersive X-ray analysis (EDAX). Transmission values ranging from 20% to 65% at varied volumes were achieved, according to the optical measurements. The energy band gaps were determined using tauc plots to be between 1.85 eV and 2.15 eV, with 4 ml having the lowest band gap value at 1.85 eV. CuO thin-film’s electrical conductivity was measured in DC, and the highest conductivity value for 4ml was 2.5x10^-8 S/cm.

Abstract: We investigated how proton implantation influences electrical characteristics of the 4H-SiC MOSFETs. Bipolar degradation in SiC is one of the key issues to be solved for utilizing the bipolar operation in SiC power devices. Its suppression with the proton implantation technique has recently been reported. If we can apply such a new technique being involved for realizing reliable SiC MOSFETs, it would give us great merit to take advantage of the body diode. However, few study has been reported of proton implanted SiC MOSFETs, to our knowledge. Thus, we fabricated 4,000 chips, applied current stress to their body diodes and subsequently evaluated them to verify statistically any effectiveness on the suppression of the bipolar degradation as well as on the electrical performance of MOSFET in order to consider its technological applicability to their mass production process. We found that proton implantation not only has little influence on the static electrical characteristics of the MOSFETs but also improves the switching characteristics.

Abstract: ZnO films were deposited by magnetron sputtering using RF power supply, in order to study the effect of substrates on quality of the prepared films. Then, growth of the ZnO films on thin AlN buffer layer and Si(100) substrates were characterized using different techniques. The surface morphology was investigated by means of scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The structural properties were investigated via X-ray diffraction (XRD) patterns, Rocking Curve as well as Pole figures. The ZnO films were textured and they had preferred orientation (002) and the crystallinity was better for ZnO/Si in the used growth conditions. The XRD results were confirmed by HRTEM. Optical properties were analyzed by photoluminescence (PL), as well as electrical characteristics were performed by C-V and I-V measurements. The dispersion orientation of these films, as indicated via the FWHM (rocking curves), is small for thin ZnO/Si. These results are considered as hopeful for piezoelectric applications.

Abstract: A simple fabrication process of an n-type silicon nanowire (SiNW) biosensor for sub-10 femtomolar (fM) concentration immunoglobulin detection was presented in this work. The SiNWs with different widths of 80-190 nm were fabricated using electron beam lithography and reaction ion etching techniques. The electrical characteristics of SiNWs with various widths were measured. And it can be observed that thin SiNW has high resistance, which is in agreement with electrical resistance theory. Furthermore, the surface of the fabricated SiNW was functionalized by 3-aminopropyltriethoxysilane for making the biosensor device to detect the binding of immunoglobulin G (IgG) molecules. The responsivity of the biosensor was investigated by observing electrical performance in response due to IgG with various concentration from 6 fM to 600 nanomolar (nM). The resistance changing ratio based on the current voltage (I-V) characteristics was analyzed and it increased with increasing of the IgG concentration. As a result, it demonstrated that the n-type SiNW biosensor has the ability to detect the IgG molecules with low concentration of 6 fM.

Abstract: The theoretical analysis of the influence of the plasma discharge temperature with non-consumable electrode on the melting of the electrode wire was carried out. The dynamics of the melting of the electrode wire and dynamics of circuit with consumable electrode arc were been investigation. The estimation of maximum values of the temperature of plasma have been made. Influence of the MIG process on the volt-ampere characteristics of the plasma discharge have been studied. These results were used for carrying out the technological experiments.

Abstract: The index system for electrical characteristics of metal-oxide surge arresters is proposed and established, which is based on rated voltage (U_r), continuous operating voltage (U_c), nominal discharge current (I_n), overvoltage protection and insulation coordination including lightning overvoltage protection level, operating overvoltage protection level and coordination coefficient (K_s). The study considers both selection and application of overvoltage protection devices for the electrical equipments in 3-35kV medium voltage power system, and comparatively calculates and analyzes the main parameters between two types metal-oxide surge arresters (without gaps and containing series gapped structures), and illustrates their technical features and puts forward suggestions on how to improve the effective utilization. The results of 10kV power distribution system are simulated to show that the conclusions are feasible and available in the practical engineering application.

Abstract: The different low temperature electrical characteristics of insulating materials, which plays an important role in superconducting power equipment, has attracted extensive attention. The cryogenic control system is applied to the independent development of superconducting electrical characteristics of insulating materials testing device. And it is designed on the basis of LabVIEW, for the test of the electrical characteristics of the insulation materials in special environment such as cryogenic temperature and vacuum. The system which uses DC source as a heat source and G-M refrigerator as a cold source, uses PID algorithm to control the heat source with the cold source so as to achieve closed-loop control. The system can make the temperature of sample from room temperature down to 6.0K within three hours and control the temperature of sample in the range of 6.0K-300.0K. The system enables temperature error not more than ± 0.5K for a long time and provides a reliable low-temperature environment which is used for study of the electrical characteristics of the insulation materials in different cryogenic temperature and vacuum environment.

Abstract: In this work, TiC-10Ni coating was synthesized on copper substrate by electro-thermal explosion directional spraying (EEUSS) method at the discharge voltage of 26kV. Electrical characteristics of the explosion were obtained. The foil was overheated in less 26 microseconds. The total electric energy supplied to the foil was 12.7 times the theoretical amount needed to melt the foil. Phase structure and microstructure of the coating were studied by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD from the coating surface consists of TiC and the solid solution of Ni, as well as the residual C. The TiC-10Ni coating, which exhibits no pores or cracks, consists of an irregular spheroidal TiC phase embedded in a nearly continuous binder. TiC particles are uniformly distributed and the size of the TiC particle of the coating is less than 1.0 μm because of the solute trapping effect.

Abstract: In this paper, we not only discuss the effect of doping concentration to conductivity but also some other factors. Such as the thickness of SiO₂ and the resistance of the conductive part (Si shell). And we have got the consequence that the higher the doping concentration is, the higher conductivity. The reason is that doping increased carrier concentration and then increased µ. The thicker the Si shell is and the shorter lengths the nanotube has, the smaller resistance the conductive part has and the higher conductivity. About the thickness of SiO₂, the situation is a little more complex. As a p-channel FET. When V_g>0, the thicker the SiO₂ is, the higher conductivity. When V_g2 is, the higher conductivity. As a n-channel FET, the situation is opposite. The reason is about potential barrier height and the location of EF. At last we repeated the previous research work and have more optimization in a reasonable parameter range. The results demonstrate that we can control conductivity and reach high transport properties for core/shell nanocable MOSFETs by combination with multiple methods.