Dielectric Breakdown of Gas Phase

In order to perform the deposition of solid materials from the luminous gas phase in low pressure, which is generally described as low-pressure plasma, it is necessary –rst to create the luminous gas phase. Fundamental investigation of the dielectric breakdown of gas phase with molecular deposition gas is considerably more dif–cult than that of non-deposition gas, because the deposition severely hampers diagnostic meas ure ment of the luminous gas phase, and the component species in the gas phase depends on the rate of deposition, which is dependent on the operation parameters. On the other hand, the breakdown occurs more or less spontaneously in many cases, and the gas phase breakdown is often taken for granted. Consequently, the understanding of gas phase breakdown of deposition gas, the monomer of low-temperature plasma polymerization, has been intuitively assumed to follow the same steps known for the dielectric breakdown of nondeposition gas, such as of argon in direct current (DC) discharge. It was recognized only recently that gas phase breakdown of molecules follows the reaction paths that are signi–cantly different from those of mono-atomic gas (e.g., Ar) [1-6].