Interelectrode Region Research Articles

Electron microscopy studies of plasma-polymerized organosilicon thin films

Plasma-polymerized thin films of hexamethylcyclotrisilazane were pyrolysed in vacuum and studied by transmission electron microscopy. Examination of the polymer film after various durations of pyrolysis revealed significant changes in their surface structure and a distinct difference in the thermal stability powder and film phases. The number of powder particles in the surface layer and their size increased with pyrolysis time. The observations showed that powder particles embedded in the film matrix were gradually exposed in the surface layer owing to a decrease in the film thickness during pyrolysis. Good agreement was obtained between the experimental and theoretical distribution curves of particle size. The identical properties of powder particles exposed in the surface of the pyrolysed film and those taken from the interelectrode region indicates that they are primarily formed in the gas phase.

Trajectory analysis of ions formed in the field emitter inter-electrode region

Ion trajectories are three-dimensionally analyzed to determine the main source of ions striking the emitting area of a field emitter. Computer calculations of the ion trajectories are made for a field emitter in the shape of a sphere radius 1000 Å, mounted on an orthogonal cone, and anode radii of 3 cm and 1 cm centered at the emitter. Approximately 10 −10 to 10 −9fraction of the ions formed at the anode by electron impact desorption reach the emitter tip. Only those residual gas ions generated in the space of a few μm around the tip are able to impinge on the emitting area. Under typical operating conditions of 10 −9 Torr, the residual gas ions striking the tip are 10 to 10 2 times greater than those from the anode, assuming an ion ejection of one ion per 10 5 electrons, and an anode potential of about 3 kV.

Bombardment of field-emission cathodes by positive ions formed in the interelectrode region

ABSTRACT Ions formed by the electron stream close to a field-emission cathode point return to the cathode. These ions can cause emission fluctuations by local work function changes, and erode the emitting surface by sputtering. An analysis of these effects with hydrogen as the residual gas over the range of tip radii from 500 A to 5000 A. which operate at voltages from I0O to 1000 volts, shows that for a given electron current the ion current to the cathode for the smaller cathode is about 16% that of the larger. However, the sputtering rate of the smaller cathode is three orders of magnitude less than for the larger cathode, mainly due to the rapid full-off of sputtering rate with ion voltage in the region below 150 volts. The lives of the cathodes, assumed to end when the radius of the cathode has been eroded by 10%, tend to be about the same, due to the lesser volume of material that has to be removed from the smaller cathode. Cathode lives may be extended by ensuring that the residual gas is hydrogen,...

Conductively connected charge-coupled device

A new kind of charge-coupled device, the conductively connected charge-coupled device (C4D) has been built and operated. This device is formed by providing self-aligned, source-drain diffusions (or implants) between adjacent, refractory electrodes of a two-phase, ion implanted-barrier CCD. These implants eliminate the inherently unstable exposed channel region presently found in CCD's with coplanar gates, without resorting to overlapping gates. Shift registers ranging from 16 to 128 b in length were evaluated and in spite of low mobilities (80 cm2/V.s) and low barrier heights (2-3 V), incomplete transfer losses of 0.2 percent per transfer were measured at 1 MHz clock frequency. Fabrication has been demonstrated to be quite compatible with p-channel refractory gate IGFET technology, and because the sensitive interelectrode region of the C4D is heavily doped, these devices should show the same reliability as conventional circuits made with the same technology.

Charge transfer in overlapping gate charge-coupled devices

A detailed numerical simulation of the free charge transfer in overlapped gate charge-coupled devices is presented. The transport are analyzed in terms of thermal diffusion, self-induced fields, and fringing fields under all the relevant electrodes and interelectrode regions with time-varying gate potentials. The results of the charge transfer with different clocking schemes and clocking waveforms are presented. The dependence of the stages of the charge transfer on the device parameters are discussed in detail. A lumped-circuit model of CCD that could be used to obtain the charge-transfer characteristics with various clocking waveforms is also presented.

Effect of Arcing on the Microstructure and Morphology of Ag-CdO Contacts

The changes in the microstructure, the composition, and the morphology of internally oxidized Ag-CdO contacts after high current arcing were investigated. The contacts were always opened on the same half cycle (60 Hz ac); thus one electrode was always the cathode, the other always the anode. Qualitative spectra of the arc at its midpoint were also taken, The results indicate that during arcing, there is a much higher concentration of Cd vapor than of Ag vapor in the interelectrode region. It is also found that the erosion of the cathode is more severe, and that the metal in the interior of the cathode craters is depleted of CdO, while a layer of Ag-Cdo is built up in the anode craters.

The properties of a metal-semiconductor-metal system based on oxide glasses

This paper reports the results of a study of the volt-amp characteristics over a broad temperature range (+200 to −100) ° C of metal-semiconductor-metal structures based on glasses in the V2O5-TeO2 system and on a V2O5 polycrystalline aggregate. The electrically formed specimens have symmetrical volt-amp characteristics with an S-type negative resistance region. The temperature dependence of the volt-amp characteristics for these specimens is different from that observed in unformed structures. It is suggested that during forming there is the precipitation of crystalline grains of VO2 in the interelectrode region and these undergo a phase change which results in the behavioral differences between the formed and unformed specimens.

Onset of rotating disturbance in the interelectrode region and exhaust jet of an MPD arc

Onset of rotating disturbance in the interelectrode region and exhaust jet of an MPD arc

Analysis of Corona Losses on DC Transmission Lines Part II - Bipolar Lines

As in the case of unipolar corona, theoretical calculation of corona losses for bipolar dc transmission line configurations involves the analysis of the nonlinear ionized field in the interelectrode region. However, the complexity of the analysis is increased considerably because of the presence of ions of both polarities in the region.

Electron-Transport Phenomena in Thermionic Converter Plasmas

An analysis of electron transport phenomena is developed in a form consistent with conditions known to exist in thermionic converter plasmas. Particular attention is given to the contribution of electron-ion collisions to the electron momentum transfer collision frequency, and the resultant dependence of the plasma transport coefficients on ion density which itself depends upon interelectrode position. Experimentally determined spatial variations of electron density and electron temperature are analyzed numerically for a variety of converter operating conditions and quantitative estimates are made of: the spatial variation of electric field intensity and electrostatic potential in the plasma, the spatial variation of electron kinetic energy flux, and the relative importance of electron energy gain and loss processes in the interelectrode region. On the basis of these results, an interpretation is made of the role played by the cesium neutralization plasma in determining converter performance.

Pulsed plasma propulsion

There are many different types of pulsed‐plasma engines, or accelerators, which may be classified by the geometry of the discharge, either a sheet or a line, and by the position of the electrodes, which are either directly in contact with the propellant, or inductively coupled with the propellant. It is the author's belief that, of all the various types of pulsed‐plasma accelerators, only the sheet‐direct‐contact accelerator will ultimately become a working engine. The arguments in support of this belief are partly of a practical nature and may even be only intuitive. There are, however, two devices which fill even this narrow description: the so‐called “pinch engine” and the purely axial accelerator illustrated in Figs. 1 and 2. Note that both are characterized by coaxial geometries and require that the discharge be axi‐symmetric. In the “pinch” type or radial accelerator, the initial discharge formed by axial currents must be turned so that the currents become radial. No turning is apparently required in the axial accelerator. However, the magnetic‐field forces are inversely proportional to the radius, and some turning will take place. It would appear that both accelerators should maintain a current sheet normal to the walls of the electrodes. This may be more easily obtained in a curved channel than in a straight one. In addition to symmetry, it appears necessary to obtain a discharge which is relatively thin and impervious to neutral particles by virtue of the high degree of ionization in the discharge. The accelerating sheet, driven by Lorentz forces, should then drive out the propellant situated in the interelectrode region. In general, the thickness of the sheet and its degree of ionization is affected by the energy available to the discharge. Low energy per discharge coupled with a high pulse rate is desirable for low capacitor weight, but is detrimental to the formation of a good driving “magnetic piston”. Experimentally, lower energy per discharge appears to be required in the radial than in the axial accelerator in order to obtain symmetric and nonporous sheet discharges or “pistons”.