Breakdown of the high-voltage sheath in metal plasma immersion ion implantation

It is suggested that breakdown of a space-charge sheath obeys similar break down laws as known for vacuum breakdown. When metal plasmas of vacuum arcs are used, the sheath between a biased substrate and plasma is very thin and the electric-field strength is very high. Field enhancement (e.g., at shar p edges of the substrate) leads to thermal instability of electron emission centers, followed by dense plasma formation which, in turn, electrically s hort circuits the sheath (breakdown). Theoretical and experimental evidence for this mechanism is presented. (C) 2000 American Institute of Physics. [ S0003-6951(00)02301-9].