Electroosmotic flow In a fused-slllca capillary column, partially filled with a buffer of one concentration and containing a second buffer of the same composition but different concentration, Is studied. The bulk electroosmotic velocity In this kind of mixed buffer system Is derived and shown to be a weighted average of the electroosmotic velocities of the pure buffers. The theory of laminar flow caused by the mismatch between electroosmotic velocities Is developed and shown to cause extra peak broadening for samples Inside the column. Good agreement with experimental results Is found. The length of new buffer Introduced by electroinjection can be determined from the variation In electrophoretic current during Injection.

The transformer coupled plasma reactor (TCP) is a low frequency, inductively coupled plasma reactor, with a gradient electromagnetic source field, such that electrons experience a secular (time average) force—the ponderomotive force. There are two electric forces and one magnetic force, the latter of which is strongly active in the TCP. The ponderomotive force has previously been explored for confinement in fusion reactors, but has not been discussed in connection with semiconductor processing. In modeling with plasma fluid equations, there is a need to include large-scale particle kinetics. The calculation of the ponderomotive force in laboratory devices is a problem, because the form of the field is often taken as a zero-curl approximation which violates Maxwell’s equations. To clarify this issue we have analyzed the ponderomotive force field in the transverse-electric electromagnetic field of a rectangular waveguide. A specific model of the TCP is analyzed. This shows that the rf-magnetic field of the TCP coil, in the range of a few gauss, creates a significant ponderomotive force at 13 MHz, which is enhanced at lower frequencies such as 1 MHz. This force acts to protect the rf window from erosion and cancel ambipolar diffusion losses, thereby improving the density uniformity of the plasma.

No abstract

No abstract

We describe the construction and performance of a new electron spectrometer for analysis of low kinetic energy electrons, 0–2000 eV. The design of the analyzer is based on computer calculations and combines many favorable properties of both the retarding and the deflection energy analyzer. The energy analyzer consists of a set of electrodes with cylindrical symmetry and a planar retarding field grid followed by an electrode system with postmonochromatic action. Therefore a differential spectrum is obtained directly. The performance of the analyzer is discussed in terms of resolution, sensitivity, luminosity, and signal-to-background. The resolution achieved is 0.5%, with a resolution of 30 meV, making it possible to resolve and study electronic vibrational levels in atoms and molecules. A few spectra of nitrogen and argon are shown as representative of the performance of the new analyzer.