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°C 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.KeywordsAmorphous hydrogenated silicon carbidePECVDMethyltrichlorosilaneWear-resistant coatingsSemiconductor films