Low temperature plasma channels generated in microcavity trenches with widths of 20-150 μm and aspect ratios as large as 10⁴:1

Low temperature plasma channels with widths as small as 20 μm, cross-sectional areas of 400-12 000 μ m2, and aspect ratios (channel length to width) of up to 104:1 have been generated on a steady state basis within sealed microcavity trenches fabricated by replica molding. With lengths up to 1 m and volumes of 10-5 -∼1 0-2 cm3, these channels are situated in a dielectric barrier structure having a transverse, buried electrode geometry and are sustained by power loadings as high as ∼1.2 kW cm-3. Current densities of ∼5-10 A cm-2 and estimated electron densities of ∼ 1011 - 1013 cm-3 are produced with a 20 kHz sinusoidal voltage of Vrms =225-325 V, rendering these channels of interest as on-chip plasma reactors or nonlinear optical conversion media. With the transversely excited, photolithographically defined microcavity structures reported here, plasma channels of at least several meters in length, and having an arbitrary, folded geometric pattern, can be generated.