Papers by Keyword: Schottky Diode

Abstract: Schottky diodes fabricated on free-standing B doped monocrystalline diamond substrate have been investigated. As expected, reverse leakage current due to Schottky barrier lowering has been observed due to the high electric field at the metal-semiconductor interface. Forward current is highest under operating temperatures between 400 and 450K due to incomplete ionization hole mobility dependence on temperature. It is demonstrated that the static device characteristics in the temperature range from 300K to 450K can be modelled by parametrizing an analytical introduced for unipolar SiC and Si diodes.

Abstract: The change in the current-voltage characteristics and in N_d-N_a values in the base of 4H-SiC Schottky diodes and JBS diodes under irradiation with 0.9 MeV electrons and 15 MeV protons has been studied. The carrier removal rate for the diodes irradiated with electrons was 0.07-0.15 cm^-1, and that in the case of protons, 50-70 cm^-1. It was shown that the devices under study retain rectifying current-voltage characteristics up to electron doses of ~10¹⁷ cm^-2. It was found that the radiation resistance of the SiC-based devices significantly exceeds that of silicon p-i-n-diodes with similar breakdown voltages. The simultaneous effect of high temperature and proton irradiation on the characteristics of 4H-SiC pn structures was examined.

Abstract: Electron irradiation of high voltage Ni/4H-SiC Schottky diodes with the dose Φ=(0.2-7)×10¹⁶cm^-2 led to increase in the base resistance, appearance of slow relaxation processes at extremely small currents, and increase of the low frequency noise. On exponential part of the current-voltage characteristics and on linear part of current-voltage characteristics in non-irradiated samples, low frequency noise always has the form of the 1/f noise. On linear part of the current-voltage characteristics in irradiated diodes the generation recombination (GR) noise predominates. Temperature dependences of the base resistivity and character of GR noise indicate that mainly Z_1/2 center contributes to the change in the parameters of irradiated samples. Capture cross section of this level, obtained from noise measurements, is within the range (8×10^-16-2×10^-15) cm² and only weakly depends on temperature.

Abstract: This paper presents a study of the Schottky barrier evolution on SBD and JBS diodes over a wide range of temperatures from 80 to 500 K. We show that inhomogeneities of the Schottky contact have a strong impact on the dependence of barrier characteristics with temperature, especially below 200 K. Analysis of the reverse bias current of such diodes at low temperature show that the barrier height depends on temperature but also on voltage.

Abstract: This paper proposes a method of characterizing silicon carbide Schottky diodes with inhomogeneous contacts in temperature sensing applications. Using the energy activation technique, temperature intervals where the effective barrier height is constant are determined. Unlike the conventional barrier which increases with temperature for inhomogeneous diodes, the effective barrier has physical meaning and can be used for sensor performance evaluation. The utility of effective barrier analysis is confirmed on fabricated Ni/4H-SiC Schottky diodes with different annealing conditions and different degrees of barrier non-uniformity. The good agreement between calculated and experimental data proves the suitable behavior of inhomogeneous diodes as sensors for different temperature ranges.

Abstract: Schottky-barrier diodes with a diameter of ~10 μm are fabricated on n-GaN epitaxial films grown by hydride vapor-phase epitaxy (HVPE) on sapphire substrates. The changes in the parameters of the diodes under irradiation with 15 MeV protons are studied. The carrier rate was found to be 130-145 cm^-1. The linear nature of the dependence N = F (D) (N is carrier concentration, and D, the irradiation dose) shows that compensation of the material is associated with transition of electrons from shallow donors to deep acceptor levels which are related to primary radiation defects.

Abstract: This work reports experimental results on surge current capability of press-pack SiC diodes: Schottky, JBS and PIN. Our investigation showed a strong improvement of electro-thermal performances of the surge current capability for the 5.5 kV JBS diodes by using press-pack encapsulation. The surge current failure analysis for the press-pack SiC diodes is described together with a simplified unidimensional model for the temperature evaluation at the failure point.

Abstract: CH₃NH₃PbI₃ thin film was deposited by a dual-source evaporation system under high vacuum (∼10⁻⁴ Pa). The crystallographic phase was analyzed by X-ray diffraction and confirmed as the perovskite structure. The optical properties of the thin film have been investigated in the spectral range 300-1800 nm. The analysis of the absorption coefficient () reveals direct allowed transition with corresponding energy 1.58 eV. The surface morphology of the film was characterized by atomic force microscopy (AFM). The observed features exhibited by CH₃NH₃PbI₃ give a vital chance to explore its application for various optoelectronic devices. To see its other potential utility, Al/CH₃NH₃PbI₃ /ITO Schottky diodes were fabricated. Based on the analyzing the I-V measurement for the Al/CH₃NH₃PbI₃/ ITO device, the basic device parameters such as barrier height and ideality factor were determined. At the low-voltage region, the current conduction in the device is ohmic type. The charge transport phenomenon appears to be space charge limited current (SCLC) at higher-voltage regions.

Abstract: The electrical behavior and stability of a temperature sensor based on 4H-SiC Schottky diodes using Ni₂Si as Schottky contact, are investigated. The ideality factor and the barrier height were found to be strongly dependent on the post-annealing temperature of the Ni contact (which lead to the formation of Ni₂Si). A nearly ideal Schottky device, with the barrier height approaching the high value of 1.7eV, and a slight temperature dependence, was obtained after an annealing at T_A=800°C. This high barrier height proves that Ni₂Si is suitable as Schottky contact for temperature sensors, able to reliably operate up to 450°C. Sensor sensitivity levels between 1.00mV/°C and 2.70 mV/°C have been achieved.

Abstract: Vertical Schottky diodes have been fabricated on low C content Si_1-xC_x and 3C-SiC epilayers epitaxially grown on Si(001) substrates. Significant leakage current was observed in 3C-SiC diodes under reverse bias, masking any rectifying behavior. This issue is far less pronounced in Si_1-xC_x based Schottky diodes which demonstrate a clear critical breakdown. Leakage current is shown to be greater in relaxed Si_1-xC_x layers. While crystalline Si_1-xC_x is not currently a viable material for high power electronics it is useful for assessing the impact lattice mismatch and crystalline quality has on the behavior of rectifiers.