Development of a novel carbon based material for integrated passive application

In this paper a novel carbon based material, tetrahedral amorphous carbon (ta-C), for integrated passive application is proposed. Two types of ta-C film for integrated passives were investigated. In the first set of sample, ta-C films were deposited with a carbon ion beam from a filtered cathodic vacuum arc (FCVA) source, together with energetic nitrogen particles (100 eV of ion energy and 0.7 mAcm^-2 of ion flux) produced by a secondary ion source, under different nitrogen partial pressures controlled by varying nitrogen flow rates to the ion beam source. This process is analogous to ion beam assisted deposition. The second set of sample was deposited by the FCVA deposition system with mixed targets, titanium/carbon and aluminum/carbon. The pattern etching of the ta-C:N, ta-C:Al or ta-C:Ti film can be done by using a RF generated ion beam source (800 eV of ion energy and 8.4 mAcm^-2 of ion flux) under oxygen partial pressure of 0.5 mTorr with the etch rate of 100 nm/min. Atomic force microscopy of the deposited films showed no presence of voids. A root mean square (RMS) surface roughness, over an area of 1 × 1 μm² is about 0.4 nm. The hardness of the deposited films are between 25 and 78 GPa. The results showed that the resistivity of the ta-C:N films were strongly dependent on the nitrogen partial pressure. The resistivity can be controlled from 9 Ω-cm to 2×10⁹ Ω-cm. Thin film resistors with 10 MΩ/□ or higher can be produced with this technique. In the a-C:Al and a-C:Ti samples, the resistivity can be controlled between i μΩ-cm to 1 KΩ-cm. Thin film resistors with 96 to 1 × 10¹⁵ Ω/□ can be produced with this technique.