Finding a promising precursor for chemical vapor deposition of carbon nitride thin films

Abstract

Carbon nitride (C 3N 4) thin films were grown on Si (100) substrates by microwave plasma enhanced chemical vapor deposition (PECVD). NH 3+CH 4, 1 H-1,2,3-triazole, hexamethylenetetramine (HMTA), and mixture of HMTA and 1 H-1,2,3-triazole were used under N 2 flow as carbon and nitrogen sources. X-ray diffraction (XRD) analyses revealed that α- and β-C 3N 4 phases were formed in the film deposited from HMTA. However, only graphitic carbon structures were observed when 1 H-1,2,3-triazole was used as the precursor. Micromechanical properties of the deposited films were also investigated using a nanoindenter. Average microhardness and Young's modulus calculated for the films deposited from HMTA were found to be 35.0±9.0 and 686.0±181.0 GPa, respectively. This relatively high hardness value is indicative of the formation of a C 3N 4 phase. X-ray photoelectron spectroscopy (XPS) studies found that the ratio of sp 3-bonded CN to sp 2-bonded CN structures is the highest for the films deposited from HMTA among the sources tested. These evidences suggest that HMTA is a promising precursor to deposit C 3N 4 films by CVD.