Plasma electron density generated by a semiconductor bridge as a function of input energy and land material

The plasma densities generated from a semiconductor bridge (SCB) device employing a capacitor discharge firing set have been measured using a microwave resonator probe in vacuum (⩽10^-5 torr). The spatial resolution of the probe is comparable to the separation between the two wires of the transmission line (≈3 mm). This method is superior to Langmuir probes in this low density, small volume application because Langmuir probe measurements are affected by sheath effects, small bridge area, and unknown fraction of multiple ions. Measured electron densities are related to the land material and input energy, Although electron densities in the plasma generated by aluminum or tungsten-land SCB devices show a general tendency to increase steadily with input power, at the higher energies, the electron densities generated from the tungsten-land SCB devices are found to remain constant