Low-k SiCxNy Films Prepared by Plasma-Enhanced Chemical Vapor Deposition Using 1,3,5-trimethyl-1,3,5-trivinylcyclotrisilazane Precursor

Abstract

Low-k silicon carbonitride (SiCxNy) films with k of 3.6–4.6 were prepared by radio frequency plasma-enhanced chemical vapor deposition at 25 to 400°C under low power density of 0.15 W/cm3, using a single source precursor, 1, 3, 5-trimethyl-1, 3, 5-trivinylcyclotrisilazane (VSZ), and Ar. At lower deposition temperatures (≤ 200°C), most cyclic VSZ structures were preserved in the SiCxNy films, resulting in a lower density (1.60–1.76 g/cm3), a lower dielectric constant (k∼3.6–3.9) and a fairly good elastic modulus of 22.0–25.0 GPa. When the deposition temperature was raised to 400°C, the cyclic N-Si-N linkages were reformed to a dense Si-N structure, with the desorption of CHx bonds, resulting in higher density (2.0 g/cm3), a dielectric constant of 4.6, and an excellent elastic modulus of 65.2 GPa. The leakage current density of SiCxNy films was reduced from 1.5×10−6 to 4.0×10−8 A/cm2 at 1 MV/cm, upon increasing the deposition temperature from 25°C to 400°C. The conduction mechanism of the SiCxNy films, except the film deposited at 400°C and tested under higher electric field, exhibited Schottky emission due to few charged defects by using a cyclic VSZ precursor and a lower plasma power density of 0.15 W/cm3.