Physical and barrier properties of plasma enhanced chemical vapor deposition alpha-SiC : N : H films

Abstract

In this work, we investigate the thermal stability and physical and barrier properties of three species of plasma enhanced chemical vapor deposition (PECVD) alpha-SiC:N:H silicon carbide films with different carbon and nitrogen contents and dielectric constants less than a value of 5.5. For comparison, one species of alpha-SiN:H film with a k value of 7.2 is also studied. It is found that the dielectric constant decreases with increasing content of carbon and decreasing content of nitrogen in the alpha-SiC:N:H film. All of the three species of alpha-SiC:N:H and the one species of alpha-SiN:H films are thermally stable at temperatures up to 500degreesC. However, degraded barrier capability and moisture resistance were observed for the alpha-SiC:N:H film with a k value of 3.5, which has a C/Si atomic ratio of 0.875. This is presumably due to the poorly crosslinked molecular structure and porosity enhancement caused by the abundant amount of carbon in the alphaSiC:N:H film.