The dual-frequency capacitively coupled plasma(DF-CCP)with inductive enhancement system is a newly designed plasma reactor.Different from the conventional inductively coupled plasma(ICP)reactors,now a radio frequency(rf)power is connected to an antenna placed outside the chamber with a one-turn bare coil placed between two electrodes in DF-CCP.This paper gives a detailed description of its structure.Moreover,investigations on some characteristics of discharges in this apparatus were made via a Langmuir probe.
BAI YangJIN ChenggangYU TaoWU XuemeiZHUGE LanjianNING ZhaoyuanYE ChaoGE Shuibing
Dry etching of 6H silicon carbide(6H-SiC)wafers in a C_4Fs/Ar dual-frequency capacitively coupled plasma(DF-CCP)was investigated.Atomic force microscopy(AFM)and X-ray photoelectron spectroscopy(XPS)were used to measure the SiC surface structure and compositions,respectively.Optical emission spectroscopy(OES)was used to measure the relative concentration of F radicals in the plasma.It was found that the roughness of the etched SiC surface and the etching rate are directly related to the power of low-frequency(LF)source.At lower LF power,a smaller surface roughness and a lower etching rate are obtained due to weak bombardment of low energy ions on the SiC wafers.At higher LF power the etching rate can be efficiently increased,but the surface roughness increases too.Compared with other plasma dry etching methods,the DF-CCP can effectively inhibit C_xF_y films'deposition,and reduce surface residues.
