Large-area surface wave plasmas using microwave multi-slot antennas for nanocrystalline diamond film deposition

An advanced slot antenna was developed and the enlargement of surface wave plasma was experimentally investigated using the array configuration of slot antennas for large-area nanocrystalline diamond (NCD) film depositions. An original-geometry slot antenna with an annular shape, designed in this work, permitted broad microwave radiations and vast extent of plasma propagations. Uniform plasmas were produced over a deposition area of 600 x 360 mm2 with densities of ∼1017 m-3 using hydrogen gas by an array configuration of five slot antennas and four rows of the array. A uniform (thickness variation: 10%) and smooth (Ra: 11 nm) NCD film deposition on a 300 x 300 mm2 borosilicate glass plate was achieved using the plasma and a mixed gas of H2/CH4/CO2.