Published online by Cambridge University Press: 15 February 2011
Although films of diamond-like carbon (DLC) and hexagonal boron nitride (h-BN) have shown low dielectric constants in the range of 3 to 4, these materials have been unsuitable for use as interconnect dielectrics due to poor thermal stability and environmental degradation. These deficiencies can be addressed by depositing DLC films free of hydrogen (a-tC) and depositing the cubic phase of BN (c-BN). The dielectric characteristics of hydrogen-free DLC and c-BN that have been deposited by pulsed-laser deposition (PLD) have been evaluated using metal-insulator-metal and metal-insulator-semiconductor structures. For comparison, the dielectric characteristics of h-BN deposited by electron cyclotron resonance (ECR) were also evaluated. Despite the superior thermal and environmental stability of the a-tC and c-BN films and the attractively low deposition thermal budget (room temperature deposition for a-tC films, 400°C for c-BN films), the films exhibit dielectric constants comparable to those of bulk diamond and bulk BN, ∼ 6. Furthermore, the a-tC and c-BN films exhibit high compressive stress in the GPa range which limits their usefulness only to those applications requiring a thin dielectric layer, e.g. diffusion barriers or encapsulants.