Crystalline SiCN: a hard material rivals to cubic BN

Growth and mechanical properties of SiCN materials prepared by microwave plasma enhanced chemical vapor deposition (CVD) as well as electron cyclotron resonance plasma CVD are reported. Large (several tens of microns), well-faceted ternary SiCN crystals were grown by microwave plasma-enhanced chemical vapor deposition. whereas amorphous SiCN films were deposited by ECR-CVD. The ternary crystalline compound (C; Si)(x)N-y exhibits a hexagonal structure and consists of a network wherein the Si and C are substitutional elements. 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 amorphous SIGN films contain only about 30 at.% N. Nano-indentation studies were employed to investigate the mechanical properties of the SiCN materials. From the load versus displacement curves. we estimated the hardness and the effective modulus of the SIGN crystals to be around 30 and 321.7 GPa, respectively. The corresponding values for the amorphous SiCN were around 22 and 164.4 GPa, respectively. These values are well above most reported values for CN films. (C) 1999 Elsevier Science S.A. All rights reserved.