Surface structure and surface barrier characteristics of boron-doped diamond in electrolytes after CF4 plasma treatment in RF-barrel reactor

Increased negatively charged nitrogen-vacancy centers in fluorinated diamond

“…In contrast to the oxygen-terminated side, the main peak on the unmasked side cannot be calibrated to the bulk diamond lattice, since the lowest binding energy peak is 2 eV lower than the main peak, and the sp 2 C-C bond has only been reported to be between 0.6 and 1.5 eV lower than the sp 3 C-C. 14 The peak with lowest binding energy has been calibrated from the measured 285.4 eV to the reported 285 eV value. The main peak at 286.9 eV mostly likely reflects a C-CF bond, 13,17 and the peaks at 288.5 eV and 290.3 eV (better seen in inset) correspond well to C-F and C-F 2 literature values. 17,18 The high concentration of C-CF bonds and the presence of C-F 2 suggest some fluorocarbon deposition from the CF 4 plasma, which also has been reported previously in the literature.…”

“…10 Recently, the fluorinated diamond electron affinity has been measured experimentally to be 2.56 eV, about 0.43 eV higher than for the oxygenterminated surface. 11 Various methods have been reported in the literature for fluorine-terminating diamond surfaces, including exposure to XeF 2 gas, 11,12 CF 4 plasma, 13 and CHF 3 plasma. 14 However, all prior work on diamond fluorination have been confined to surface chemistry, whereas this work studies the effect of surface fluorination on the charge states of NV centers in bulk diamond.…”

“…17,18 The high concentration of C-CF bonds and the presence of C-F 2 suggest some fluorocarbon deposition from the CF 4 plasma, which also has been reported previously in the literature. 13 We estimate the polymerized fluorocarbon layer to be about 3 nm thick, given that the C-C bond signal disappears at a 60 stage tilt, which reduces the analysis depth by half.…”

Surface structure and electrochemical characteristics of boron-doped diamond exposed to rf N2-plasma

“…Especially processing in a RF plasma reactor has been found as very ''aggressive'' to the diamond surface [20,21]. It could corrode the surface in a nanometre range, also resulting in a non-diamond carbon phase [21]. Such defects modify the electronic surface barrier in contact with electrolytes and also degrade the response to redox reactions [8,20,21].…”

“…Especially processing in a RF plasma reactor has been found as very ''aggressive'' to the diamond surface [20,21]. It could corrode the surface in a nanometre range, also resulting in a non-diamond carbon phase [21].…”