This paper contains results of theoretical studies of the breakdown voltage mechanism in direct current nitrogen discharges from 0.5 micrometers up to 100 micrometers. The aim of this paper is to contribute to a better understanding of the electrical breakdown in microgaps and to determine modified Paschen curves. For that purpose, the breakdown voltage curves in nitrogen microdischarges have been calculated by using a Breakdown Voltage and Current Density in Microgaps Calculator including ion-enhanced field emission. The obtained results clearly show that electrical breakdown across micron-size gaps may occur at voltages far below the minimum predicted by the standard scaling law that could be explained by the enhance of the secondary electron emission yield due to the quantum tunnelling of electrons from the metal electrodes to the gas phase. The high electric fields generated in microgaps combined with the lowering of the potential barrier seen by the electrons in the cathode as an ion approaches lead to the onset of ion-enhanced field emissions and the lowering of the breakdown voltage. Based on the analysis of the obtained results we may conclude that the gap size, the gas pressure, enhancement factor, the effective yield and work function strongly affect the breakdown voltage characteristics. Presented results could be useful for determining minimum ignition voltages in microplasma sources as well as the maximum safe operating voltage and critical dimensions in microdevices

Full text: IJEIR_2303_FINAL.pdf