Dielectric Diode Research Articles

Modification of phase boundaries and oxide layer of Ti-TiO2-oxidant system, by intensive thermo - chemical oxidation with rapid thickness growth of dielectric oxide layer n-conductivity type

Titanium oxidation process is thermodynamically spontaneous, its speed depends on kinetic and diffusion process parameters. According to optical measurements results, the oxide layer formed on titanium has a thickness of only 1.7 nm. A layer of this thickness is formed at room temperature within two hours, and in 40-50 days it grows to 3.5 nm. Created under natural conditions, TiO2 is a non-stoichiometric dielectric oxide of n-type conductivity. The goal of this work is to significantly speed up the oxidation process by thermochemical oxidation and achieve oxide thicknesses over 100?m. An intensive thermo-chemical process creates disorders with oxygen vacancies excess (O???) and with a smaller representation of interstitial disorders (Ti ? ?). In this work, starting from the mentioned disorders - defects, by thermo-chemical oxidation of Ti - TiO2 - oxidant system, by choosing numerous oxidants, a composite system was obtained with a significant increase in disorder degree of active centers - defects about 1018 to 1020/cm3. Thus, the significantly disordered structure of Ti - TiO2 - oxidant system can be a very active dielectric diode in Ti - TiO2 - M system (where M is some vaporized metal). Such a diode has stable rectification properties at high temperatures up to 106 times, which makes it more reliable compared to the active element of semiconductive p-n diode system.

Space charge limited current in a gap combined of free space and solid

The paper presents a model of the space charge limited (SCL) electron conduction in a gap with a combination of free space and dielectric solid. The SCL electron current density J is solved numerically to obtain the voltage scaling of J∼VGn, and n is found to be between n=3/2 (a vacuum gap) and n=2 (a dielectric diode). The dependence of n is calculated as a function of dielectric constant, electron mobility, and the relative length scale between the free space and dielectric solid. The model has been used to explain a recent experiment.

SELF-CONSISTENT PHENOMENOLOGICAL THEORY OF CHARGE INJECTION AT THE CONDUCTOR/INSULATOR INTERFACE

ABSTRACT Self-consistent mean-field model of charge injection based on the matching of electric displacement and electrochemical potential in the electrode and the insulator is extended so as to account for discreteness of charge carriers. The improved scheme includes both the Schottky barrier lowering due to the individual image charge and the barrier change due to the field penetration into the injecting electrode. Applications of the theory to the cases of high-permittivity dielectric capacitors and organic light-emitting diodes are exemplarily presented.

A hydrodynamic model of the electric strength of dielectric diodes

A model of the electric breakdown of thin-layered metal-dielectric-metal structures, used to choose the working parameters and for the diagnostics of solid-state microelectronic devices, is described.

Calculation of the Critical Parameters of Self-Exciting Processes in the Electrothermal Destruction of Dielectric Diodes

This article examines the effect of a solid-state low-temperature plasma on processes involved in the fatigue of metal-dielectric-metal junctions subjected to external direct current. The formation of defects in the dielectric layer is accompanied by the injection of electrons from the cathode and current self-excitation. A physical-mathematical model of the process is proposed and calculated results are compared with an experiment.

Quasi-Optical Sensors for Investigation of Acousto-Electromagnetic Phenomena of Popocatepetl Volcano

This article focuses on meteorological electronics based on the space research of acoustic-electromagnetic phenomena caused by Popocatepetl volcano (Mexico). The main purpose is to present two different types of quasi-optical sensors, one of them is formed by a modulator based on a surface oriented p,i,n structure with “deep” junctions; and by a silicon detector (avalanche photodiode with separated regions of absorption and multiplication: APDSAM). This system guarantee both good sensibility and wide range of sensing, sub-millimeter and millimeter range. This sensor has the advantage that can be realized as a planar array. On the other hand, for the remote measurement of basic meteorological parameters and chemical state by means of radiobrightness temperatures (radiometer systems) a low noise receiver on the base of dielectric waveguide and Schottky diodes cooled by means of cryoelectronic element is used.

High-frequency conductivity of a dielectric diode with cylindrical electrodes in the case of double injection in the drift-velocity saturation regime

This article presents a calculation of the high-frequency conductivity of a dielectric diode with cylindrical electrodes in the case of double injection in the drift-velocity saturation regime. Formulas are obtained for high-frequency conductivity and are used to construct graphs. A comparison is made with the case of a planar diode. It is shown that the conductivity of a dielectric diode working in the drift-velocity saturation regime changes with frequency in roughly the same manner for both planar and cylindrical electrodes. However, the conductivity of the latter may be considerably greater than that of the former, and the conductivity of the cylindrical diode is greater, the greater the ratio of the radii of the cathode and anode.

Current Transients in the Insulator Determined by Space Charge and Diffusion

AbstractThe mathematical problem of one‐carrier space‐charge‐limited current (SCLC) step‐response in a perfect insulator is solved with a digital computer taking carrier diffusion into account. Curves of forward‐current density vs. time are presented with an error analysis and a brief discussion of the parameter influence for the case of a dielectric diode under different values of applied pulse voltages in the steady‐state current range where a square‐law behaviour begins to show up and inclusion of diffusion in the treatment is indispensable. The lowering of the voltage in this range deprives gradually the mean features of the SCLC transient ascertained for the diffusion‐neglected case. Last of all only the diffusion‐dominated current in the very beginning of the transients remains. The maximum time for observing the diffusion contribution to the pulse current estimated by Schilling and Schachter proves to be understated.

Space-charge waves and high-frequency negative resistance of SCL diodes†

In this paper the small-signal operation of space-charge-limited (SCL) diodes is studied in detail, by using a quantitative method previously suggested by the author. Typical cases, such ns SCL dielectric diodes with traps or field-dependent mobility, the punched-through SCL diode, the bulk negative mobility amplifier with zero ion density, the SCL vacuum diode, are included. The transport of space charge and the inertia of the carrier velocity with respect to electric field variations are both taken into account, in order to explain high-frequency negative resistance effects. ‡Permanent address: Department of Electronics, Polytechnieal Institute, Bucharest, 62, Romania.

Trapping and transit-time effects in high-frequency operation of space-charge-limited dielectric diodes: Frequency characteristics

The small-signal high-frequency operation of space-charge-limited dielectric diodes is theoretically studied by taking into account both shallow trapping and transit-time effects. Traps are assumed to be uniformly distributed in space but to have an arbitrary distribution in energy. By using the expression of the diode impedance calculated in a previous paper, two limit cases are discussed in detail: the effect of ‘slow’ and, respectively, ‘fast’ traps at frequencies where electron transit-time is comparable to the signal period. In a high-frequency range, the operation of a diode having ‘slow’ traps, even in high density, is close to that of a diode without traps. The operation of a diode having a relatively high density of ‘fast’ traps can be restricted to considerably lower frequencies. The computed high-frequency characteristics of diodes with ‘slow’ shallow levels indicated the appearance of a negative resistance for certain frequency ranges if the density of the trapping states is sufficiently high. This negative resistance can be explained as a typical transit-time effect.

Detection properties of space-charge-limited dielectric diodes in the presence of trapping

Detection properties of space-charge-limited dielectric diodes in the presence of trapping

A high-frequency negative resistance in dielectric diodes with a high density of shallow traps

The high-frequency impedance of the space-charge-limited dielectric diode is calculated by taking into account transit-time and trapping effects. It is assumed that the trapping states are shallow, of relatively high density and that the electron relaxation time in the presence of trapping is much longer than the electron transit time. The computed frequency characteristics indicate the existence of a negative resistance for certain frequency ranges. This negative resistance is explained as a transit-time effect.

On the space-charge noise suppression in solids at low injection level

The current noise spectral density distribution functions are computed for a dielectric diode working in the space-charge-limited régime, making use of the Van Vliet and Fassett general method and the hypothesis concerning the injected carrier drift on a quasi-neutral background. A suppression effect of the noise due to space charge was found, and an amplifying one due to the traps.

Quantitative Comparison of Solid-State Microwave Detectors

A method for quantitative comparison of solid-state microwave square-law detectors is presented. The threshold response of the square-law detectors are compared for unit video bandwidth using the concept of noise equivalent power (NEP). NEP is the microwave input power required for unity signal-to-noise ratio in a 1 Hz bandwidth at the output of the detector. Contours of constant NEP in the microwave (RF) and video frequency plane clearly describe the dependence of threshold sensitivity on both video and radio frequencies, and thereby provide comparison of the threshold sensitivities of devices over the entire video and RF frequency spectrum. A criterion for the upper RF power lid of square-law operation for detectors is also presented. Dynamic range for a device can be found using this criterion and the threshold sensitivity of the device. Six solid-state detection devices are described briefly, then compared on the basis of the foregoing concepts. Four of these devices are familiar: the point-contact and planar Schottky-barrier ("hot carrier") diodes, and the tunnel and back diodes. Two relatively new devices are also discussed: the so-called "hot carrier" thermoelectric detector, and the space-charge-limited (SCL) dielectric diode.

Position correlations and space-charge noise suppression in solids at low frequencies

Van Vliet and Fassett have settled the pattern for a more direct approach to the current noise problem. This method is applied here to the space-charge-limited current regime in a semiconductor. In this approach, position correlations between carrier concentrations were computed within the Debye-Huckel approximation, and the Green function for the carrier pulse drift on a non-neutral ground was determined with the aid of a specific physical hypothesis (drift without broadening). Noise spectral density distribution functions were computed in closed form for (i) the ideal dielectric diode (without traps) and (ii) the real dielectric diode (with compensated traps) in the limiting cases of very high and very low levels of injection. A space-charge noise suppression effect was found in all cases, except for the trap-compensated solid at very low level of injection. The suppression effect is highly complicated because of the trapping processes and is exerted on the pure shot noise as well as on the generation-recombination noise.

Effect of traps distributed in energy over the a.c. response of thin film transistor and dielectric diode

Effect of traps distributed in energy over the a.c. response of thin film transistor and dielectric diode

Small-signal Theory of Space-charge-limited Diodes†

ABSTRACT A unified approach for small-signal theory of spaee-charge-limited (SCL) unipolar diodes is suggested. SCL planar vacuum diode and SCL solid-state diodes with various velocity field-dependences are taken into account. The typical small-signal method used allows us to solve problems, both already studied and new, of SCL diodes' small-signal operation in a simple and direct manner. As an illustration of this method, the SCL solid-state diode having a carrier velocity field-dependence of the form υ = μEc(E/Ec)m (0≤M≤1) is studied in detail. The impedance of SCL dielectric diodes with traps, taking into account both trapping and transit-time effects, is presented. A method of physical interpretation of small-signal SCL diodes' response is suggested and the possibility for the appearance of a high-frequency negative conductance is discussed. Particularly, the negative conductance calculated for the dielectric diode with a high density of shallow traps is explained.

Some computed and measured characteristics of CdS space-charge-limited diodes

The mode of operation of the dielectric diode is discussed. Computed solutions for diodes with indium-CdS-gold structures are presented for three types of CdS crystal doping; the ideal case, shallow traps compensated by donors and deep traps compensated by donors. Theoretical I–V characteristics, potential and field distributions and electron density distributions are presented. These are discussed and compared to some experimental characteristics.

Space-charge reduction of shot noise for space-charge-limited current in solids

The shot noise in a dielectric is calculated under space-charge-limited current conditions at low frequencies. The results apply to the dielectric diode, where generation-recombination noise is not important.

Characteristics of the dielectric diode and triode at very high frequencies : S. Brojdo, Solid-State Electron., Vol. 6, 1963, pp. 611–629

Characteristics of the dielectric diode and triode at very high frequencies : S. Brojdo, Solid-State Electron., Vol. 6, 1963, pp. 611–629