Crystalline SiCN: a hard material rivals to cubic BN

Growth and mechanical properties of SiCN materials prepared by microwave pl asma enhanced chemical vapor deposition (CVD) as well as electron cyclotron resonance plasma CVD are reported. Large (several tens of microns), well-f aceted ternary SiCN crystals were grown by microwave plasma-enhanced chemic al vapor deposition. whereas amorphous SiCN films were deposited by ECR-CVD . The ternary crystalline compound (C; Si)(x)N-y exhibits a hexagonal struc ture and consists of a network wherein the Si and C are substitutional elem ents. While the N content of the crystalline compound is about 50 at.%, the extent of Si substitution varies and can be as low as 10 at.%. The amorpho us SIGN films contain only about 30 at.% N. Nano-indentation studies were e mployed to investigate the mechanical properties of the SiCN materials. Fro m the load versus displacement curves. we estimated the hardness and the ef fective modulus of the SIGN crystals to be around 30 and 321.7 GPa, respect ively. The corresponding values for the amorphous SiCN were around 22 and 1 64.4 GPa, respectively. These values are well above most reported values fo r CN films. (C) 1999 Elsevier Science S.A. All rights reserved.