Hydrogenated Amorphous Silicon Carbide Films as Perspective Tribological Coatings and Semiconductor Layers

Abstract

Amorphous hydrogenated silicon carbide (a-SiC:H) films have been deposited from methyltrichlorosilane (MTCS) in a 40.56 MHz PECVD reactor with an additional substrate bias on crystalline silicon wafers. The films as wear-resistant coatings and semiconductor layers contain about 60-70 and 70-80 at% Si, respectively. Film thicknesses were about 0.2- 0.4 µm. Film morphology and scratch test investigations show that the films are homogeneous and have rather good adhesion to the substrates. From nanoindentation tests it follows that a-SiC:H coatings exhibit the hardness up to 10 GPa and elastic modulus of 118 GPa. The annealed at 600 0C samples have higher hardness then the as-deposited films (by about 25%). Ball-on-plane tests have reveled that the abrasive wear resistance of the covered substrates is 1.5-4 times higher than that of the un-covered ones. So, despite the comparatively low hardness, the a-SiC:H films demonstrate good tribological properties. The possible mechanisms describing the tribological properties of a-SiC:H coatings are discussed. a-SiC:H films prepared under special conditions possess good semiconductor properties. Particularly, dark conductivity, photosensitivity and optical band gap were 10-9- 10-11 S/cm, 103-104 and 2.1-2.7 eV, respectively, which enables the films to be used as possible active layers in semiconductor devices.