Structure and optical properties of carbon nitride films deposited by magnetron sputtering

Atomic rearrangement of sputtered amorphous carbon nitride thin films during growth

“…This trend indicates that substantial amounts of nitrogen atoms are also etched by the incoming species. The liberated nitrogen atoms recombine to form N 2 molecules, which can either diffuse to the surface or stay inside the film inducing the formation of voids (low density) [7,13,14]. The ERDA and NRA measurements confirm these arguments and reveal a systematic presence of a significant amount of hydrogen and oxygen.…”

“…Indeed, in amorphous carbon nitride, the sp 2 bonds can obviously be either CC or CN. The decrease observed for E Tauc optical gap with the increasing rf power, appears to be related to the local bonding changes due to the desorption of nitrogen from the growing films (a decrease of the CN proportion), increasing the concentration of Csp 2 sites (graphitization) and therefore, the CC network connectivity [14].…”

“…We present in Table 1, the values of the positions of the G and D peaks, x G and x D , and their full width at half maximum, DG and DD, versus the RF power. To supply these results, we report in the same table the Tauc gap (E Tauc ) presented previously [13,14]. E Tauc is conventionally defined by the Tauc relationship aE=B(EÀE Tauc ) 2 and obtained by optical transmission spectroscopy [15].…”

“…This band can be decomposed for all the films, into sub-bands at 1220, 1400, 1570 and 1650 cm À1 . The peak around 1220 cm À1 can be attributed to sp 3 CN bonds, while the peak around 1650 cm À1 can be assigned to CN double bonds [13,14,[16][17][18]. The modes at 1400 and 1570 cm À1 are still debated [5,6,8].…”

“…The modes at 1400 and 1570 cm À1 are still debated [5,6,8]. The absorption band lying between 2000 and 2500 cm À1 suggests the presence of the chemical groups isonitrile and nitrile (triple bonded CN), which may terminate a chain and, thus, determines the extent of the void structure [7,14]. This result is confirmed by the band around 3400 cm À1 , associated with the OH vibration, suggesting a high atmospheric contamination by oxygen and water in good agreement with the ERDA and NRA results discussed above.…”