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Remote plasma sources have traditionally been used in semiconductor processing applications such as dry removal of photoresist, where the capability of delivering a large flux of atomic oxygen into a semiconductor process chamber, with little of the associated plasma used to dissociate the oxygen, has made them attractive. With the development of fluorine-compatible remote plasma sources, a range of new application opportunities has opened up. In remote cleaning of CVD chambers, the remote plasma source is positioned before the process chamber, and a stream of atomic fluorine from the source is flowed into the chamber, where it can effectively clean a wide variety of materials such as SiOz, Si3N4, and W. The cleaning process is purely chemical, with no associated in-situ plasma which can cause degradation of the process chamber. In exhaust gas abatement, the remote plasma source is located between the outlet of the etch or deposition process chamber and the mechanical pump. By adding appropriate gases, the exhaust stream from the chamber can be converted to a form which can be managed more readily. Using an robust toroidal plasma source design, the ASTRONTM remote plasma source has been used to address both of these areas. As an atomic fluorine source, over the typical operating range of 2-10 Torr several SLM of gases such as NF3 can be fully dissociated. As an exhaust gas abatement device, with operating pressure in the 0.1-1 .O Torr regime, abatement of perfluorocompounds (PFC's) at greater than 95% levels has been demonstrated. Using a variety of techniques -FTIR, RGA, and sample etchingthe operation of this source technology and issues such as transport of atomic fluorine over substantial distances has been investigated.The atmospheric pressure plasma jet (APPJ) is a unique plasma source operating at atmospheric pressure. The APPJ operates with RF power and produces a stable non-thermal discharge in capacitively-coupied configuration. The discharge is spatially and temporally homogeneous and provides a unique gas phase chemistry that is well suited for various applications including etching, film deposition, surface treatment and decontamination of chemical and biological warfare (CBW) agents. A theoretical model shows electron densities of 0.2-2x10" cm-3 for a helium discharge at a power level of 3-30 W ~m -~. The APPJ also produces a large flux, equivalent of up to 10,000 monolayer s-', of chemically-active, atomic and metastable molecular species which can impinge surfaces several cm downstream of the confined source. In addition, the efforts are in progress to measure the electron density using microwave diagnostics and to benchmark the gas phase chemical model by using LIF and titration. 158

We will report recent results from the Sustained Spheromak Physics Experiment (SSPX) in which we measure peak electron temperatures greater than 3OOeV in driven spheromak discharges. The SSPX spheromak plasma (0.31m major radius, 0.13m minor radilts) is driven for up to 4msec by a DC coaxial source (a Marshall gun), which is powered by a 2MJ capacitor bank. The plasma is contained inside a tungsten-coated copper Hux conserver which maintains stability against global tilting modes.Plasm temperature and density are measured by a multi-point Nd:YAG Thomson scattering system and CO2 interferometer, respectively; II complete temperature profile is obtained during each discharge. We use a 2d Grad-Shafronov solver to reconstruct the MHD equilibrium current profile from edge magnetic field data. The reconstruction can be further constrained by using insertable magnetic probes to measure the magnetic field components inside the coaxial injector region. Best operation of the spheromak is obtained after extensive preconditioning, which includes a high temperature bake, glow discharge cleaning, helium plasma scrubbing, and titanium getter. In this way, we obtain discharges with Z.,, 4 . 5 . Without such conditioning, the spheromak plasmas exhibit rapid decay of the magnetic field after the drive is turned off and central electron temperatures are 50eV or less.Our results also show that magnetic fluctuatious must be reduced in order to obtain high temperatures. We minimize the magnetic Huctuations by maintaining the gun current just above the ejection threshold of the gun for several msec following a large initial high-current formation pulse. As the plasma evolves, the magnetic fluctuations fall to 6B/B<0.5% and T. rises from ilOOeV tomore thmi 300eV. Peaked temperature proiiles are observed with T. > V,,,. Transport analysis yields a thermal diffusivity xs < 10m2/s with peak P. > 10%.We are now exploring ways to increase the spheromak magnetic field strength from the present peak of about 0.25T. Higher fields should allow higher plasma temperature at fixed density. While many disch.uges exhibit a stiff relationship between gun current and spheromak magnetic field, we observe steadily rising magnetic field energy at constant gun current when we eliminate the large initial formation pulse and turn on the gun more slowly. These discharges exhibit large voltage fluctuations, which are the subject of present research. New gun designs are being developed which will help us understand the source of these voltage fluctuations. Los Alamos National Labomtory Los Alamos, NM 87545 USA 'Air Force Research Laboratory Albuquerque, NM87177 USAThe Field Reversed Experiment -Liner (FRX-L) is a plasma injector for Magnetized Target Fusion (MTF) development at Los A l a " National Laboratory. The MTF project goal is to adiabatically compress a target plasma to achieve fusion conditions in a pulsed experiment in near future. FRX-L is designed to produce a field reversed configuration (FRC) plasma that will be translated and fast compressed in a...