Optical and electrical properties of nitrogen incorporated amorphous carbon films

Nitrogen incorporated amorphous carbon (a-C:N) films on silicon (111) wafer , quartz, and Ti/C substrates with nitrogen concentration up to 20 at. % ar e prepared by filtered arc deposition. The nitrogen concentration and area density of the films were measured by Rutherford backscattering. The electr ical properties of the films were investigated by Hall electrical measureme nts. The optical properties of the films were characterized by ultraviolet- visible and infrared reflection spectrometry. Results indicate that the opt ical band gap and area density of a-C:N films decrease with increasing nitr ogen pressure, accompanied with an increase of nitrogen concentration and r eflectivity of the films. Furthermore, the influence of nitrogen concentrat ion on the optical band gap of the films is discussed. The dielectric const ant, refractive index and absorption coefficient of a-C:N films in infrared region were investigated. The results indicate that the optical constants of a-C:N show considerable variation with wave number and nitrogen content. The variation of optical properties and optical constants of a-C:N films m ay be due to the development of graphite-like structure with the increasing of nitrogen content in these films. (C) 2000 American Institute of Physics . [S0021-8979(00)00406-0].