Abstract
This thesis mainly focuses on the influence of precursor gases and pressure, and/or the applied negative dc/rf bias for the synthesis of three different amorphous carbon nitride (a-C:N) compounds using ECR-CVD system. One is the a-C:N thin films on Si substrate for promising electron field emitters and for low-dielectric-constant (low k) materials as an interlayer dielectric (ILD) with the application of dc or rf bias voltage; Others are the nano-structural materials for a-C:N nano-tips and -rods on Si and porous alumina template substrates with the application of the dc bias by ECR-CVD. a-C:N nanotips and well-aligned a-C:N nano–rods can be predicted and expected to have potential applications in flat pannel display field emitters, optic, electronic and optoelectronic devices. The superior field emission characteristics of a-C:N nanotips were synthesized for the first time by an ECR-CVD system by applying a negative dc bias to a Si substrate and using a mixture of C2H2, N2 and Ar as precursors. An onset emission field can be as low as 1.5 Vμm-1, which is significantly lower than other carbon-based electron field emitters. The effect of argon induced graphitization on the electron field emission properties of the a-C:N thin films has also been analyzed in this work. Well-aligned a-C:N nano-rods with a diameter of about 100-250 nm and a length of about 50-80 □m on a porous alumina template were successfully synthesized by an ECR-CVD system in which a negative dc bias was applied to the substrate holder of graphite to promote the flow of ionic fluxes through the nano-channels of the alumina template in microwave excited plasma of C2H2 and N2 as precursors. The a-C:N thin films have been synthesized on Si for low k materials by using an ECR-CVD system with an application of negative rf bias to the silicon substrate in a mixture of C2H2 and N2 as precursors. The dielectric constants of a-C:N thin films have been reported as low as 1.4, at 1 MHz, respectively. OES was used for these studies to investigate and analyze the activated radicals in the plasma. Various analytical techniques, such as FE-SEM for the surface and cross section morphology, AFM for the surface morphology and roughness, TEM for the atomic-scale structure, FTIR for chemical bonding structure, Raman spectroscopy for carbon bonding state, and XPS and AES for relevant chemical elements, were employed to characterize their properties.