Enhancement of mechanical properties of organosilicon thin films deposited from diethylsilane

Abstract

A strong demand exists for improved low-k intermetal dielectric materials, such as organosilicons, to enhance the performance of ultralarge scale integrated circuits. Pulsed-plasma enhanced chemical vapor deposition was used to deposit organosilicon thin films from diethylsilane and oxygen. Fourier-transform infrared (FTIR) analysis showed significant organic content as well as hydroxyl and silanol moieties in the as-deposited materials. FTIR showed a complete removal of hydroxyl groups after annealing at 400°C for 1h. This removal indicates a condensation reaction between proximal hydroxyl groups leading to the formation of additional Si–O–Si linkages, which would increase both the hardness and modulus of the film. Mechanical property measurements were in accordance with this hypothesis, as both the hardness and modulus increased by over 50% after annealing. Film structure and properties were strongly dependent on the precursor feed ratio.