SiCN thin films were synthesized by a radio frequency chemical vapor deposition (RFCVD) system on P|type Si (1 0 0) wafers using C 2 H 4 , SiH 4 and N 2 as raw materials. In order to get rid of the oxygen absorbed on the surface and improve the characteristics of electron field emission, Ar + ions of low energy were used to bombard the samples. The field emission characteristics of SiCN thin films before and after Ar + bombardment were studied in the super vacuum environment of 10 -6 Pa. It was showed that the turn|on field (defined as the point where the current|voltage curve shows a sharp increase in the current density) decreased from 38 V/μm before bombardment to 25 V/μm after bombardment. And the maximum emission current density increased from 159.2 to 267.4 μA/cm 2 . The composition before and after Ar + bombardment was compared using X|ray photoelectron spectroscopy (XPS). Our results illustrated that the field emission characteristics were improved after the bombardment of Ar + . SiCN thin films were synthesized by a radio frequency chemical vapor deposition (RFCVD) system on P type Si (1 0 0) wafers using C 2 H 4, SiH 4 and N 2 as raw materials. the oxygen absorbed on the surface and improve the characteristics of electron field emission, Ar + ions of low energy were used to bombard the samples. The field emission characteristics of SiCN thin films before and after Ar + bombardment were studied in the super vacuum environment of 10 -6 Pa. It was showed that the turn | on field (defined as the point where the current | voltage curve shows a sharp increase in the current density) decreased from 38 V / μm before bombardment to 25 V / μm after bombardment. And the maximum emission current density increased from 159.2 to 267.4 μA / cm 2. The composition before and after Ar + bombardment was compared using X | ray photoelectron spectroscopy (XPS). Our results illustrated that the field emi ssion characteristics were improved after the bombardment of Ar +.