Archimedes Technology Group, Inc.

Ga Technologies, Inc.

Richard L Freeman

Robert L Miller

Tihiro Ohkawa

Sergei Putvinski

Hiroyuki Ikezi

John Gilleland

A material separator includes a chamber and electrode(s) to create a radially oriented electric field in the chamber. Coils are provided to generate a magnetic field in the chamber. The separator further includes a launcher to propagate a high-frequency electromagnetic wave into the chamber to convert the material into a multi-species plasma. With the crossed electric and magnetic fields, low mass ions in the multi-species plasma are placed on small orbit trajectories and exit through the end of the chamber while high mass ions are placed on large orbit trajectories for capture at the wall of the chamber.

High frequency wave heated plasma mass filter

A filter and a method for separating ions in a partially ionized plasma according to their mass includes a chamber with crossed electric and magnetic fields established therein. A feed, including metal atoms having ionization potentials in a low range, and gas atoms having an ionization potential in a high range, is introduced into the chamber. An electron temperature below the low range is generated to partially ionize the feed by dissociating the metal atoms from the gas atoms, and by ionizing the metal atoms into light and heavy ions according to their mass to charge ratio. The light and heavy ions are then influenced by the crossed electric and magnetic fields to separate the light ions from the heavy ions.

Partially ionized plasma mass filter

A multi-mass filter for separating particles of a multi-species plasma includes a chamber, which defines an axis. A radial electric field is crossed with a magnetic field (E&times;B) to move the particles of different mass (M , M and M ) on respective trajectories into respective first, second and third regions. Specifically, particles M are confined in the first region, while both particles M and M are ejected from the first region into the second region and only the particles M are ejected from the second region into the third region.

Multi-mass filter with electric field variations

A device for generating a plasma includes an enclosed chamber and an antenna positioned adjacent the wall of the chamber. A ceramic shield is mounted on the wall, with the antenna located between the wall and the ceramic shield. There is also a barrier that is mounted on the wall with the ceramic shield being between the barrier and the antenna element. An alternating voltage source is provided to energize the antenna element to generate a plasma in the chamber. In operation, the ceramic shield isolates the antenna from the plasma in the chamber, and the barrier prevents the deposition of material components from the plasma on the ceramic shield.

Shielded rf antenna

A system and method for initiating and maintaining a plasma in a chamber, in accordance with the helicon dispersion relation, requires an antenna for radiating RF energy into the chamber. An interferometer, or some similar device, is used in the system to monitor the plasma density level in the chamber, as the plasma is being produced. The plasma density level is then used to control the variable characteristics of the RF energy in accordance with the helicon dispersion relation.

System and method for initiating plasma production

A multi-mass filter for separating particles according to their mass-charge ratio includes a chamber for receiving a multi-species plasma that includes particles therein having different mass-charge ratios (with M,<M,<M,). Inside the chamber, which defines an axis, a radial electric field is crossed with a magnetic field (E&lE;B) to move the particles (M,, M,and M,) on respective trajectories into respective first, second and third regions. For one embodiment, the filter is configured so that a,B,is held constant in the expression for cut-off mass, M,&equals;ea,B,/(8V,). For this embodiment, only the heavier particles M,are ejected into the third region (M,>M,) and only the intermediate particles M,are ejected into the second region (M,>M,). In another embodiment, the radial electrical field is increased outwardly from the axis to a radial distance a,(r,) at a first rate. The electrical field is then increased radially outward between a,(r,) and a radial distance a,(r,) at a lower rate. This electric field configuration defines the first region between the axis and a,(r,), and the second region between a,(r,) and a,(r,). The third region is located radially beyond the second region. Accordingly, with M,&equals;er,B,/(8*(V,V,)) and M,&equals;e(r,&minus;r,)B,/(8*V,), particles M,are confined in the first region, while both particles M,and M,are ejected from the first region into the second region. The particles M,are, however, confined in the second region and only the particles M,are ejected from the second region into the third region.

Multi-mass filter

A plasma mass filter using a helical magnetic field for separating low-mass particles from high-mass particles in a multi-species plasma includes a cylindrical outer wall located at a distance &ldquo;a&rdquo; from a longitudinal axis. Also included is a coaxial cylindrical inner wall positioned to establish a plasma chamber between the inner and outer walls. The magnetic field is generated in this chamber with an axial component (B,) and an azimuthal component (B,), which interact together with an electric field to create crossed magnetic and electric fields. The electric field has a positive potential, V,, on the inner wall and a zero potential on the outer wall. With these crossed magnetic and electric fields, a multi-species plasma is moved through the chamber with a velocity, v,, high-mass particles in the plasma (M,) are ejected into the outer wall and low-mass particles (M,) are confined in the chamber during transit of the chamber to separate the low-mass particles from the high-mass particles, where M,<M,<M,, and where M,&equals;(ea,(B,&plus;B,)/8v)&lcub;f(B,/B)&rcub;.

Plasma filter with helical magnetic field

A method for judging whether a group of semiconductor devices have sufficiently short carrier lifetimes to make them suitable for use in high speed electronic circuitry. A determination is made as to the satisfactory carrier lifetime for a pn junction in the devices. A capacitance value representative of the pn junction, when reverse biased, is also determined. The pn junction is placed in series with an inductor sized so that the resonant frequency of the inductor and the pn junction, when reversely biased, is substantially equal to the reciprocal of the carrier lifetime. An oscillating voltage is applied to the series combination of the junction and the inductor, the voltage having a fundamental frequency near but above the resonant frequency and an amplitude greater than a predetermined level which is in the range of 3-5 volts. Finally, the device under test is rejected should an output taken across the pn junction show a substantial frequency component below the fundamental frequency.

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Del Mar, CA, United States of America

Richard L Freeman