Fundamentals of Breakdown & Plasma Generation

Discharge formation can be predicted using the empirical Paschen’s law depending on the gas mixture, the electrode material and geometries as well as the gap-pressure product (p ∙ d). This approach describes the Townsend ionization processes and suggests that the breakdown voltage (V_b) should increase for small inter-electrode gap.

Meanwhile, numerous experimental, simulation studies have shown a V_b drop for small inter-electrode distances, lower than a micrometer [1]. This challenges the reliability of gaseous insulation at the nanoscale, a major issue in view of the miniaturization of electronic systems [2]. The most promising theory explaining these deviations refers to the field emission, which is an elementary mechanism not part of the original hypothesis.

This experimental study introduces an original statistical approach: the breakdown voltage measurement is repeated a large number of times to estimate the probability density function unraveling the competing elementary processes, highlighting the field emission mechanism.

V_b is measured in argon at different pressure (0.5 - 2 bar) for inter-electrode gap from 100±25 nm to 6.0 μm. A grounded gold plated silicon wafer acts as a cathode and a needle with a tip radius curvature of 20 μm is used as the anode [3].

[1] D B Go and A Venkattraman 2014 J.Phys.D:Appl.Phys. 47 503001

[2] C H Chen, J Andrew Yeh and P J Wang 2006 J. Micromech. Microeng. 16 1366–1373

[3] B. Disson, N. Bonifaci, O. Lesaint, C. Poulain, R. Dussart and S. Iséni, 2025, Phys. Rev. E, submitted

Funding acknowledgement

The research was supported by the French National Research Agency (ANR) with the project MIDICODE585(ANR-22-CE51-0022-01).