A mechanism of PFM erosion and redeposition in gaps

Uni-polar auto-oscillating secondary emission discharges (UASED) can arise between two surfaces with different electron emission connected by a magnetic field. High secondary e–e coefficient and primary electrons of high energy are necessary for development of UASED. High voltage oscillations lead to enhanced erosion of the contacting surfaces and deposition of C:H films stimulated by RF plasma–surface interaction. The RF discharge broadens, transverse transport increases, so the surfaces far from the main plasma also participate in plasma–surface interaction. UASED induces high electric fields in shadowed and remote gaps. These fields stimulate a-C:H films growth due to activation of polymerization on the surface of volatile hydrocarbons penetrating the gaps.