An electrical, optical and electron paramagnetic resonance study of room temperature deposited CNx films on Si

Carbon nitride films were deposited onto n-type silicon substrates by room temperature sputtering and suitable nitration. Two series of samples were prepared, differentiated by the applied substrate bias while growing. They were examined by means of electrical, optical and electron paramagnetic resonance (EPR) measurements in order to reveal their electronic properties. The electrical measurements showed that the films deposited under a positive bias (#1) were insulators, while those with a negative one (#2) were semiconductors. Then, EPR spectra were taken in order to clarify the role the inter-atomic bonding formation can play on the electrical properties of the films. The results showed that the sp2-sp3 ratio was 25:58 and 65:25, respectively, for the #1 and #2 films. Such behaviour was correlated to the deposition conditions and the films showed to be suitable for use in microelectronics devices.