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High-density reactive species plasmas uniformly covering large surface areas are required for semi-conductor processing. Novel, self-matched plasma sources using microwave solid state generators have been developed for this purpose. The technology applied, based on automatic frequency tuning, allowed to eliminate the impedance matching system. Large surface plasmas have been achieved by using a distribution of elementary sources. A big campaign of plasma density measurement using a Langmuir probe has allowed to create a database for different plasma conditions for a single source. Thanks to an internally developed software, the density obtained with several sources in various distribution configurations has been simulated. The position and the power of each source have been optimized and the calculations have been validated by experimental measurements. High plasma densities >1011 cm−3 over large areas >400 mm in diameter with only 13 plasma sources have been achieved with all tested gases. An increase of compactness i.e., increasing the sources number over the same area, allows to have the same plasma surface while increasing the plasma density up to 5 × 1011 cm−3.

In microwave plasmas with the presence of a magnetic field, fast electrons could result from collisionless energy absorption under electron cyclotron resonance (ECR) conditions. In this case, electrons are trapped between the two poles of the magnetic field and rotate at the cyclotron frequency ω c e. When crossing a zone where the cyclotron frequency equals the microwave frequency ( ω c e = ω), electrons see a steady electric field in their reference frame and are constantly accelerated by the right handed polarized (RHP) wave. When the plasma density reaches the so-called critical density nc at which ω p e 2 = ω 2 ± ω ω c e, where ω p e is the plasma electron frequency, the left handed polarized (LHP) electromagnetic wave can excite electrostatic waves that can produce collisionless electron heating and fast electron generation by Landau damping. In this study, a combination of the Langmuir probe and trace rare gas optical emission spectroscopy (TRG-OES) is used to analyze the electron energy probability function (EEPF) in microwave (2.45 GHz) low-pressure argon plasmas excited at ECR in a dipolar magnetic field. While both TRG-OES and Langmuir probe measurements agree on the effective electron temperature ( T e A l l) from 1.6 to 50 mTorr, TRG-OES, which is more sensitive to high energy electrons, shows that the EEPF is the sum of two Maxwellian populations: one described by T e A l l and a high energy tail characterized by a temperature T e Tail. Spatially resolved-TRG-OES measurements show that the high-energy tail ( T e Tail) in the EEPF is spatially localized near the magnet, while the effective electron temperature ( T e A l l) stays constant. The ratio between the high energy tail and the effective temperatures is found to increase with the absorbed microwave power and decrease with increasing pressure. The former phenomenon is ascribed to a rise in ECR heating due to a stronger RHP wave electric field and to an enhanced absorption of the LHP waves. On the other hand, the decrease in the ratio is attributed to a smaller magnetic confinement of the electrons (increase in the collision frequency), which lessens ECR heating and to a decrease in the LHP field intensity at the resonant position, which impedes the conversion into electrostatic waves.

International audience; Microwave plasma sources distributed on a planar matrix configuration can produce uniform bi-dimensional plasmas free from magnetic field in the 100 Pa pressure range. In argon, such uniform sheets of plasma have been obtained with ion densities in the range of 1012 to 1013 cm-3 with microwave power ranging from 0.4 to 2 kW. The electrical characterization of the plasma has been investigated using a cylindrical Langmuir probe. A first feature concerns the plasma potential that exhibits quite high values due to the large increase in the electron temperature towards the source plane where the microwave electric field is applied. Secondly, the decrease in the electron temperature observed when increasing the microwave power can be justified by the apparition of multi-step ionization mechanisms via metastable and higher excited states of Ar atom. The concentration and temperature of Ar(3P2) metastables have been measured by laser diode absorption spectroscopy. The results indicate that the presence of Ar(3P2) metastables is significant at 2 cm from the source plane with concentration and temperature values varying from 1010 to 1011 cm-3 and from 500 K to 1300 K, respectively, as functions of argon pressure and microwave power. An analytical model using a few simplifying assumptions provides a plasma picture in good agreement with the experimental results.

Copper/hydrogenated amorphous carbon (a-C:H) and nickel/a-C:H composite films have been deposited on Si substrates by combining sputter-deposition of metal and microwave plasma-assisted chemical vapor deposition of carbon from argon–methane mixtures of various concentrations. The deposition rate of films was found to vary between 10 and 25 nm/min depending on the CH 4 concentration in the gas phase. The crystallographic structure of films was identified by X-ray diffraction (XRD) techniques. Diffraction peaks of the face-centered cubic (fcc) Cu phase were always detected in the XRD patterns of Cu/C films. Diffraction peaks of the fcc Ni phase appeared in the XRD patterns of Ni/C films deposited from gas mixtures containing less than 5% of CH 4 . Diffraction peaks of Ni and Ni 3 C phases were detectable in the XRD patterns of Ni/C films deposited from a gas phase containing 10% of CH 4 . For Ni/C films deposited with a CH 4 concentration in the range 15–30%, the diffraction peaks in the XRD patterns were only ascribable to the Ni 3 C phase. Beyond 30% of CH 4 in the gas phase, the structure of Ni/C films became progressively amorphous as the CH 4 concentration increased. The grain size of Cu, Ni and Ni 3 C was determined as a function of the CH 4 concentration. The residual stresses in Cu/C films were very low and independent of the CH 4 concentration in the gas phase (or composition of films). For Ni–C films, the maximum value of compressive residual stresses was −0.6 GPa for films deposited with 20% of CH 4 in the gas phase (or for Ni/C films containing pure Ni 3 C phase). The electrical resistivity of films determined by four point probe measurements as well as the hardness and elastic modulus of films deduced from nanoindentation measurements were studied as functions of the CH 4 concentration in the gas phase.

The development of high performance Electron Cyclotron Resonance Ion Sources (ECRIS) greatly depends on the feasibility of sophisticated magnetic structures with high field gradients. The most powerful ECRIS are based on superconducting technologies. The application of high magnetic field techniques like split polyhelices permits to build low cost prototypes with a short development time, this is a key issue to develop a Research and Development program in ion sources science. We describe here the first ECRIS cusp prototype we have built with this technology. A 5 T field gradient on a 90 mm distance have been measured on the main axis of the helices for a 15000 A current intensity applied. This contribution summarizes the latest experimental achievements with the split polyhelix magnetic structure.

In order to drastically reduce the power consumption of a microwave ion source, we have studied some specific discharge cavity geometries in order to reduce the operating point below 1 W of microwave power (at 2.45 GHz). We show that it is possible to drive an electron cyclotron resonance ion source with a transmitter technology similar to those used for cellular phones. By the reduction in the size and of the required microwave power, we have developed a new type of ultralow cost ion sources. This microwave discharge system (called COMIC, for COmpact MIcrowave and Coaxial) can be used as a source of light, plasma or ions. We will show geometries of conductive cavities where it is possible, in a 20 mm diameter chamber, to reduce the ignition of the plasma below 100 mW and define typical operating points around 5 W. Inside a simple vacuum chamber it is easy to place the source and its extraction system anywhere and fully under vacuum. In that case, current densities from 0.1 to 10 mA/cm(2) (Ar, extraction 4 mm, 1 mAe, 20 kV) have been observed. Preliminary measurements and calculations show the possibility, with a two electrodes system, to extract beams within a low emittance. The first application for these ion sources is the ion injection for charge breeding, surface analyzing system and surface treatment. For this purpose, a very small extraction hole is used (typically 3/10 mm for a 3 microA extracted current with 2 W of HF power). Mass spectrum and emittance measurements will be presented. In these conditions, values down to 1 pi mm mrad at 15 kV (1sigma) are observed, thus very close to the ones currently observed for a surface ionization source. A major interest of this approach is the possibility to connect together several COMIC devices. We will introduce some new on-going developments such as sources for high voltage implantation platforms, fully quartz radioactive ion source at ISOLDE or large plasma generators for plasma immersion, broad or ribbon beams generation.

International audience; Plasma scaling up can be achieved by distributing elementary microwave plasma sources on planar rectangular networks. These so-called matrix plasmas can generate uniform sheets of plasma over a wide argon pressure range, from 7.5 to 750 Pa, with densities between 1012 and 1013 cm−3. In order to estimate the capabilities of matrix plasmas for PACVD processing in terms of deposition rate and uniformity, SiOCH and SiNCH films were deposited using TMS (tetramethylsilane), as the organic gas precursor of silicon, mixed with oxygen or nitrogen flows. Plasmas of O2 / TMS and N2 / TMS gas mixtures can be sustained between 5 and 25 Pa. Variations in the deposition rate as a function of microwave power and nitrogen partial pressure are reported. Thickness uniformity of SiOCH and SiNCH films was measured across a silicon wafer. The obtained deposition rates exceed 1.3 μm/min and the films present a uniformity better than 5% on 75 mm diameter silicon wafers. Composition of the films has also been analyzed by XPS as a function of process parameters: microwave input power, composition of gas mixture, and N2 partial pressure. In particular, these analyses have shown a very low yield of nitrogen incorporation when using N2 gas as nitrogen precursor and high Si and Si-Si bonding contents in the films, probably due to a strong fragmentation of the TMS precursor in the high density plasma.

Conference Proceedings can be submitted to Review of Scientific Instruments; International audience; The LPSC is involved for several years in a challenging R&D effort dedicated to study the production of pulsed radioactive ions beams with high ionization efficiency. The driving force of these studies is the long term Beta Beam scenario study. The ins and outs of the Beta Beams source requirements will be recalled. The generation of the high magnetic field requires the use of helix techniques developed at LNCMI. As a first approach, a cusp structure has been chosen. 3D simulations were used to define the geometry of the helices. The CAD mechanical design of the magnetic structure has been performed at LPSC and was optimized to decrease the total volume of the source. The first 60 GHz magnetic structure (helices coils in their tanks, electrical and water cooling environment) should be available before the end of 2009

International audience; In a previous study, a planar plasma reactor comprising 4 × 3 elementary microwave plasma sources distributed according to a square lattice matrix configuration was first characterized with argon. In this work, the objective is to characterize these so-called matrix plasmas with hydrogen in view of surface processing applications. In the absence of a static magnetic field, hydrogen plasmas can be sustained uniformly in the medium pressure range from 10 to 70 Pa. Using a cylindrical Langmuir probe, plasma density and electron temperature have been investigated at a distance of 20mm from the source plane as functions of pressure and microwave power. The results show that the electron temperature Te is of the order of 1.2 eV and that plasma densities up to a few 1011 cm−3 can be reached. Under the same experimental conditions, optical emission spectroscopy measurements have been performed in order to determine the gas temperature and the degree of dissociation of hydrogen. The gas temperature, calculated from the α–Fulcher Q branch emission band (2–2) d 3П−u a 3Σg, varies from 600 to 850K ± 50 K. The degree of dissociation has also been determined by using a spectroscopic method based on emission line intensities of Hα, Hβ and H2 (2–2) d 3 П −u a 3Σg (N = 1) species. The maximum degree of dissociation of 50% has been obtained for the operating conditions corresponding to the highest plasma density.

The experimental study of the pulsed-mode operation of the PHOENIX-V2 electron cyclotron resonance ion source at 28 GHz has clearly demonstrated, when increasing the repetition rate of the high-frequency power injection at frequencies higher than 1 Hz, the reality of a transient current peak occurring at the very beginning of the plasma discharge. This regime was named Preglow as an explicit reference to the classical Afterglow occurring at the microwave pulse end. After the transient Preglow peak, the plasma regime relaxes to the classical steady-state one. Experimental argon pulses for charge states from 2+ to 8+ are presented. The current observed during the Preglow peak can reach intensities on the order of 1 mA for low charge states (Ar4+). A zero-dimension theoretical model of electron cyclotron resonance (ECR) gas breakdown in a magnetic trap is presented in detail. Results of the simulation are compared with the experimental Preglow peaks and discussed.

International audience; Plasma scaling up can be achieved by distributing elementary microwave plasma sources over two or tri-dimensional networks. This concept is applied to a planar reactor comprising 4 x 3 microwave plasma sources distributed according to a square lattice matrix configuration. In each elementary plasma source, the plasma is produced at the end of a coaxial applicator implemented perpendicularly to the planar source. An argon plasma can be sustained in the medium pressure range from 7.5 to 750 Pa. The sheet of plasma thus obtained becomes uniform at a distance from the source plane of 15 mm, i.e. less than half the 40mm lattice mesh. Using a cylindrical Langmuir probe, plasma density and electron temperature have been investigated as functions of pressure and microwave power. Results show that the plasma can reach densities between 10(12) and 10(13) cm(-3) with a uniformity better than +/- 3.5%.

International audience; A-PHOENIX is a new compact hybrid electron cyclotron resonance ion source (ECRIS) using a large permanent magnet hexapole (1.92 Tesla at the magnet surface) and High Temperature Superconducting Solenoids (3 Tesla) to make min-|B| structure suitable for 28 GHz CW operation. The final assembly of the source was achieved at the end of june 2007. The first plasma of A-PHOENIX at 18 GHz was done on August the 16th 2007. The technological specificities of A-PHOENIX are presented. The large hexapole builded is presented and experimental magnetic measurements show that it is nominal with respect to simulation. A fake plasma chamber prototype including thin iron inserts showed that the predicted radial magnetic confinement can be fulfilled up to 2.15 Tesla at the plasma chamber wall. Planning of experiments scheduled until end 2008 is presented.

A careful study of pulsed mode operation of the PHOENIX electron cyclotron resonance (ECR) ion source has clearly demonstrated the reality of an unexpected transient current peak, occurring at the very beginning of the plasma breakdown. This regime was named the preglow, as an explicit reference to the afterglow occurring at the microwave pulse end. After the transient preglow peak, the plasma regime relaxes to the classical steady state one. Argon preglow experiments performed at LPSC are presented. A theoretical model of ECR gas breakdown in a magnetic trap, developed at IAP, showing satisfactory agreement with the experimental results is suggested.

The threshold conditions to maintain millimeter and submillimeter-size discharges of xenon with microwaves are experimentally determined. The threshold electric field required to sustain the plasma is reported as a function of gas pressure. The influence of the size of the dielectric cell in which the discharge is produced is also shown. The scaling laws are deduced from the threshold electric field measurements, assuming a few additional simplifying assumptions. The results are compared with data obtained with argon discharges sustained by surface waves in capillary tubes and the hypotheses assumed for the calculations are discussed.

Neutrino oscillations have implications for the Standard Model of particle physics. The CERN Beta Beam has outstanding capabilities to contribute to precision measurements of the parameters governing neutrino oscillations. The FP7 collaboration EUROnu (2008-2012) is a design study that will review three facilities (Super-Beams, Beta Beams and Neutrino Factories) and perform a cost assessment that, coupled with the physics performance, will give means to the European research authorities to make decisions on future European neutrino oscillation facilities. "Beta Beams" produce collimated pure electron (anti)neutrinos by accelerating beta active ions to high energies and having them decay in a storage ring. Using existing machines and infrastructure is an advantage for the cost evaluation; however, this choice is also constraining the Beta Beams. Recent work to make the Beta Beam facility a solid option will be described: production of Beta Beam isotopes, the 60 GHz pulsed ECR source development, integration into the LHC-upgrades, insure the high intensity ion beam stability, and optimizations to get high neutrino fluxes. The costing approach will also be described. Copyright ?????? 2012 by IEEE.

The discovery that the neutrino changes flavor as it travels through space has implications for the Standard Model of particle physics (SM)[1]. To know the contribution of neutrinos to the SM, needs precise measurements of the parameters governing the neutrino oscillations. This will require a high intensity beam-based neutrino oscillation facility. The EURO?????? Design Study will review three currently accepted methods of realizing this facility (the so-called Super-Beams, Beta Beams and Neutrino Factories) and perform a cost assessment that, coupled with the physics performance, will give means to the European research authorities to make a decision on the lay-out and construction of the future European neutrino oscillation facility. "Beta Beams" produce collimated pure electron neutrino and antineutrino beams by accelerating beta active ions to high energies and letting them decay in a race-track shaped storage ring. EURO?????? Beta Beams are based on CERNs infrastructure and the fact that some of the already existing accelerators can be used. To use existing machines is a strong advantage for the cost evaluation, however this choice is also constraining the Beta Beams. In this article we describe recent work that has made the Beta Beam facility a solid option for neutrino production: new ideas and developments to produce and collect different Beta Beam isotopes, the 60 GHz pulsed ECR source development, the integration of Beta Beams in the upgrade program for LHC, work to ensure the very high intensity ion beam stability in the different machines, and optimizations of the decay ring to get high neutrino flux at a gamma boost of 100. Copyright ?????? 2011 by IPAC'11/EPS-AG.