Effects of annealing temperature on the optical, bonding, structural and electrical properties of nitrogenated amorphous carbon thin films grown by surface wave microwave plasma chemical vapor deposition

We have studied the effects of annealing temperature (AT) on the properties of nitrogenated amorphous carbon (a-C:N) films grown at room temperature (RT) on quartz substrates by surface wave microwave plasma chemical vapor deposition (SWMP-CVD) using camphor alcohol gas as carbon plasma sources. The thickness, optical, bonding, structural and electrical properties of the as-grown (RT) and anneal-treated in range from 100 to 500°C of a-C:N films were measured and compared. The film thickness is decreased rapidly with increasing AT above 350°C. The wide range of optical absorption characteristics is observed depending on the AT. The optical band gap of as-grown a-C:N films is approximately 2.8 eV, gradually decreased to 2.5 eV for the films anneal-treated at 300°C and beyond that it decreased rapidly up to 0.9 eV at 500°C . Visible-Raman Spectroscopy (Raman) revealed the amorphous structure of as-grown a-C:N films and, the growth of nanocrystallinity of a-C:N films upon increase of AT. Raman and Fourier transform infrared spectroscopy (FTIR) analyses respectively shown the structural and composition of the films can be tuned by optimizing the AT. The change of optical, bonding, structural and electrical properties of SWMP-CVD grown a-C:N films with higher AT was attributed due to the fundamental changes in the bonding and band structure of the a-C:N films.