Electrical reliability of low dielectric constant diffusion barrier (a-SiC:H) for copper interconnect

The electrical stability and reliability of the Trimethylsilane (3MS) based a-SiC:H (SiC) film was investigated for the first time. Capacitance-Voltage (C-V) characteristic instability was observed due to polarization at high electrical field and electron injection at low electrical field. By adding nitrogen content in the film, the dielectric constant and leakage current are reduced but the time dependent dielectric breakdown (TDDB) lifetime becomes worse at high nitrogen content. It is suggested that the SiC deposition can be optimized at moderate nitrogen content to compromise all film properties.