Microstructure and properties of ultrathin amorphous silicon nitride protective coating

Abstract

The effect of N content on the structure and properties of rf reactively sputtered a-SiN, has been studied by Rutherford backscattering spectrometry (RBS), x-ray reflectivity (XRR), ellipsometry, and nano-indentation. The N content in the film increased with the NZ concentration in the sputtering gas until the SisN4 stoichiometry was reached. The hardness of a-SiN, increased with density, which in turn increased with the N content. The maximum hardness of 25 GPa and density of 3.2 g/cm3 were attained at the stoichiometric SisN4 composition. With the application of protective overcoat for magnetic disks in mind, thin a-SiN, films were deposited on CoPtCr media to examine their coverage, pinhole density, and wear resistance. According to x-ray photoelectron spectroscopy (XPS), the minimum thickness of a-SiN, required to protect the CoPtCr alloy from oxidation was 10 A, which was 10 A thinner than that of the reference a-CN,. A statistic model showed the lower coverage limit of a-SiN, can be attributed to its high density, which corresponds to 93% bulk density of SisN4. Compared with 45 8, a-CN, coated disks, 15 A a-SiN, coated disks had lower pinhole defect density and superior wear resistance.

Structure and composition of silicon nitride and silicon carbon nitride coatings for joint replacements

“…These coatings were deposited at a higher temperature and/or at a higher Si target power. This is in agreement with literature, as it suggests higher deposition temperatures and nitrogen fractions for the formation of a crystalline (or polycrystalline) Si 3 N 4 structure [10,50,51]. For implant applications, an amorphous structure may be an advantage compared to a polycrystalline structure, as an amorphous structure generally is more uniform with less corrosion paths such as grain boundaries [32].…”

Different substrate materials effect on structure of ta-C films by Raman spectroscopy for magnetic recording sliders

“…The ratio of sp 3 /sp 2 carbon atoms is one of the most important factors governing the quality of DLC films. In general, the higher this ratio, the closer the DLC film properties approach those of diamond [4]. At present, highly sp 3 hydrogen-free DLC films, tetrahedral amorphous carbon (ta-C), are becoming the preferred means of coated sliders because of their unique combination of desirable properties, such as high wear resistance, a smooth morphology, low friction coefficient, chemical inertness, pin-hole free and optical transparency [5][6][7][8].…”

“…Having excellent hardness and corrosion resistance, diamond-like carbon (DLC) films have been commercially applied as an overcoat film for magnetic recording sliders in hard disk drive (HDD) [1][2][3][4]. The properties and the quality of DLC films strongly depend on their microstructure, which is commonly considered as an amorphous mixture of sp 2 and sp 3 hybridized carbon atoms.…”

Understanding the Role of Nitrogen in Plasma-Assisted Surface Modification of Magnetic Recording Media with and without Ultrathin Carbon Overcoats

“…However, particle generation remains an issue with FCVA-deposited COCs, which may lead to slider and media wear along with flyability issues 17 19 22 . Since magnetron sputtering is a simple, inexpensive and industrial-friendly process for the deposition of overcoats with negligible particle generation, the industry and researchers are still using this process for the fabrication of carbide and non-carbon-based overcoats 23 24 25 26 . For example, recently Rose et al 25 26 have fabricated a variety of carbide and non-carbide overcoats such as SiN, SiC, TiSiN, TiSiC by magnetron sputtering.…”