Roles of Ions and Free Electrons in the Synthesis of Mechanically Hard Amorphous-CNx Films Using a Dissociative Excitation Reaction of BrCN with the Ar Electron Cyclotron Resonance Plasma

Abstract

A dissociative excitation reaction of BrCN with the Ar electron cyclotron resonance (ECR) plasma was applied to synthesize mechanically hard amorphous carbon nitride (a-CNx) films. The hardness of the films has been measured by a nanoindenter to be at most 15 GPa under the maximum loading force of 50 mN. The self-bias voltage, -Vself, and the I–V characteristics have been measured to discuss the mechanism of hardening of the a-CNx films. It was confirmed that -Vself causes the Ar ion bombardment on the surface of the films, leading to the high hardness value of the films without applying an external bias voltage.