Production and application of low-energy, high-current electron beams (original) (raw)
Related papers
Surface alloying by pulsed intense electron beams
Vacuum, 2005
Results of numerical calculations and experimental studies of the thickness of modified layers, distribution of implanted materials, microstructure and phase composition inside the layers following pulsed electron beam treatment are presented. Possible physical mechanisms of the alloying process are discussed. The improvements of surface properties, especially corrosion resistance against liquid lead, are presented. It is shown that corrosion of OPTIFER IVc steel by liquid lead containing 8 Â 10 À6 at% oxygen is avoided by alloying Al into the surface.
Generation of electron-beam produced plasmas and applications to surface modification
2004
NRL has developed a number of hollow cathodes to generate sheets of electrons culminating in a 'Large Area Plasma Processing System' (LAPPS) based on the electron-beam ionization process. Beam ionization is fairly independent of gas composition and produces low temperature plasma electrons (-0.5 eV in molecular gases) in high densities (10 -10 cm ).
Electron-beam-generated plasmas for materials processing
Surface and Coatings Technology, 2004
The results of investigations aimed at characterizing pulsed, electron-beam-produced plasmas for use in materials processing applications are discussed. In situ diagnostics of the bulk plasma and at the plasma/surface interface are reported for plasmas produced in Ar, N 2 , and mixtures thereof. Langmuir probes were employed to determine the local electron temperature, plasma density, and plasma potential within the plasma, while ion energy analysis and mass spectrometry were used to interrogate the ion flux at an electrode located adjacent to the plasma. The results illustrate the unique capabilities of electron-beam-produced plasmas and the various parameters available to optimize operating conditions for applications such as nitriding, etching, and thin film deposition. D
Small pulsed electron-ion sources for radiation technologies and surface modification of materials
A new type of small, combined pulsed electron-ion source for radiation technologies and surface modification of materials is reported. The source consists of a high voltage generator and particle emitter in the form of a vacuum diode. Explosive electron emission is used for production of electron beams and explosive ion emission for production of ion beams. The main parameters are the source output are: kinetic energy 200-700 keV, pulse length 0.3-1.0 ps, electron beam current 0.5-6 kA, ion beam current 0.1-200 A for ions of various conducting materials. The main applications of the device are presented.
A review of microelectronic film deposition using direct and remote electron-beam-generated plasmas
IEEE Transactions on Plasma Science, 1990
Soft-vacuum-generated electron beams employed to create a large area plasma for assisting chemical vapor deposition (CVD) of thin films are reviewed. The electron beam plasma is used both directly, where electron impact dissociation of feedstock gases plays a dominant role, and indirectly in a downstream afterglow, where electron impact dissociation of feedstock reactants plays no role. Rather, photodissociation and metastable atom-molecule reactions dominate in the downstream afterglow. To better understand electron-beam-created plasmas using a slotted ring cathode, the transmitted beam spatial intensity profiles have been quantified from initial generation at a slotted line-shaped cold cathode through acceleration in the cathode sheath and propagation in the ambient gas. To better understand the role of photodissociation in downstream plasma-assisted CVD, the VUV output spectrum and VUV generation efficiency from electron-beam-excited plasmas have been measured. The properties of films deposited via both direct electron-beam-generated plasma-assisted CVD and downstream afterglow CVD are reviewed and compared to conventional plasma assisted CVD films. I. SOFT-VACUUM ELECTRON BEAM GENERAnON A. Thermionic Sources T HE conventional means of producing electron beams uses thermionic cathode sources to emit electrons, which are accelerated in an ambient pressure typically below 10-4 torr. Thermionic emitters have limited application because of the low required operating pressure and the likelihood of poisoning from ambients other than inert gases. Wide area (> 10 em") electron beams are usually not generated from thermionic cathodes, further precluding the use of this type of source in many practical applications. B. Glow Discharge Sources A glow discharge environment provides a simple means to produce wide-area electron beams without the need of Manuscript
Japanese Journal of Applied Physics, 2011
The channel spark discharge was used as a high-current density (up to 30 kA/cm 2 ) relatively low-energy (<20 keV) electron beam source in a pulsed plasma deposition (PPD) gun. The PPD gun was used for the deposition of thin films by pulsed ablation of different target materials, at a background gas pressure in the 10 À3 -10 À5 Torr range. The parameters of the electron beam generated in the modified PPD gun were studied using electrical, optical, and X-ray diagnostics. It was found that a higher background pressure stimulates a denser plasma formation between the gun output and the target, that restricts the energy delivery to the beam electrons. Namely, the efficient (up to $74%) transfer of the initially stored energy to the electron beam is realized at the background gas pressure of 10 À4 Torr. Conversely, at a pressure of 10 À3 Torr, only 10% of the stored energy is acquired by the energetic electrons. It was shown that the modified PPD gun, owing to the extremely high energy density delivered by the electrons to the target, may be applied for the deposition of a wide variety of different insulators, semiconductors, and metals. A selection of materials such as diamond-like carbon (DLC), cadmium telluride (CdTe), cadmium sulphide (CdS), zinc oxide (ZnO), tungsten, and tungsten carbide (WC) have been deposited as thin films and the properties and deposition rates of the deposited thin films are discussed.
Recent advances in surface processing with metal plasma and ion beams
Surface and Coatings Technology, 1999
Surface processing by metal plasma and ion beams can affected using the dense metal plasma formed in a vacuum arc discharge embodied either in a ''metal plasma immersion'' configuration or as a vacuum arc ion source, as well as by many other well-established methods. In the former case the substrate is immersed in the plasma and repetitively pulse-biased to accelerate the ions across the sheath and allow controlled ion energy implantation + deposition, and in the latter case a high energy metal ion beam is formed and ion implantation is done in a more-or-less conventional way. These methods have been used widely; here we limit consideration to work carried out at the Lawrence Berkeley National Laboratory. A number of advances have been made both in the plasma technology and in the surface modification procedures that enhance the effectiveness and versatility of the methods. Recent improvements in plasma technology include dual-source plasma mixing, ion charge state enhancement, and some scale-up of the hardware. We have made and explored some novel kinds of surface films and modified layers, including for example doped diamond-like carbon (DLC ), novel multilayers, alumina and more complex ceramic materials such as mullite (3Al 2 O 3 .2SiO 2 ), high temperature superconducting films, and others. Recent research has included investigations of these and other surface materials for many different basic and applied applications, such as for high temperature tolerant protective coatings, biomedical compatibility, surface resistivity tailoring of ceramics, novel catalytic surfaces, corrosion resistance of battery electrodes, and more. Here we briefly review the fundamentals of the techniques, and describe some of the applications to which the methods have been put at
2003
This article presents the construction of a fast, intense electron beam generator, several of its operational properties and its preliminary applications. A fast filamentary discharge produced in a tube filled with Argon gas at pressure of about 0.1 torr. An electron beam is obtained with a current intensity of about 0.6 A for a 25 ns duration. The length of the filamentary discharge and the behavior of the beam in the magnetic field are examined. The interaction of the beam with different targets was investigated by Scanning Electron Microscope. It is also demonstrated that the device can be used to drill holes of several tens of microns in diameter and it can be used for material coating.