Pulsed Breakdown Behaviors across Microgaps at Various Atmospheres

With the rapid miniaturization and integration of electronic and electromechanical devices, especially for vacuum micro devices, it is urgent to study the electrical breakdown behaviors of pulsed breakdown at microscale and explore its underlying principle. In this paper, the influence of atmospheric pressure and electrode geometries on pulsed breakdown at microscale was studied by the home-built electro-optical measuring system. Results show that when the gap width is less than 5 μm, the role of gas molecules density or gas pressure inside the gap could be eliminated which means that the breakdown process is similar as the vacuum breakdown. For different electrode geometries, when the gap width is larger than 15 μm, the breakdown voltage remains the same regardless of the electrode geometries, whereas difference behaviors can be observed when the gap width is less than 15 μm, and these results can be analyzed from different breakdown mechanism such as field electron emission, ion-enhanced field emission and Townsend avalanche. The results presented in this paper would be of a great help for better understanding the physical mechanism of pulsed breakdown at microscale.