Makoto Ryoji

Tribological characteristics of Si-containing diamond-like carbon films under oil-lubrication

Abstract Tribological behaviors of Si-containing diamond-like carbon (DLC) and DLC films deposited by an electron beam excited plasma (EBEP)–CVD system were investigated for applications to mechanical components. The ball-on-disc tests against bearing steel with oil-lubrication were performed for the Si-containing DLC and the DLC-coated carburized Cr–Mo steel discs. Two different oils with and without zinc dialkyldithiophosphate (Zn-DTP) additives were used as lubricants. The Si-containing DLC films deposited at SiH 4 flow ratios of 2.8 and 12.5% showed low coefficients of friction and wear resistance when lubricated in the oil with additives. The results from X-ray photoelectron spectroscopy (XPS) analysis indicated that it was due to the effect of formation of a boundary lubrication film including ZnO, ZnS, FePO 4 , FeS and FeS 2 compounds on the lubricated contact region.

New etching system with a large diameter using electron beam excited plasma

A new etching system using electron-beam-excited plasma (EBEP) has been developed. This EBEP system is able to steadily produce a high-density plasma with a large diameter by introducing a high-current low electron beam into the etching chamber. The nonuniformity of plasma density and floating potential in an 8-inch wafer are improved up to ±2.5% and ±2 V, respectively. Anisotropic etching of n+-poly-Si in a pure Cl2 plasma is achieved with a high etch rate of 360 nm/min. The etching selectivity is 40 for poly-Si/photoresist and 150 for poly-Si/SiO2. These experimental results show that the EBEP etching system is suitable for manufacturing advanced ULSI.

Diamond-like carbon films deposited by electron beam excited plasma chemical vapor deposition

Abstract An electron beam excited plasma (EBEP) system can produce a high-density plasma by introducing a high-current and low-energy electron beam into a process chamber. Diamond-like carbon (DLC) films prepared by EBEP-CVD systems were investigated for deposition rate, dynamic hardness and microstructure. The substrate bias voltage, substrate position and source gas were varied as the deposition parameters. It was found that when a higher negative bias voltage was applied to the substrate during deposition, the concentration of the sp 3 sites, the size of the graphite crystallite and the total hydrogen content decreased, whereas the density increased. The differences in the substrate position and source gas strongly affected the microstructural properties of the deposited DLC films.

Deposition of microcrystalline silicon by electron beam excited plasma

Hydrogenated microcrystalline silicon (μc-Si:H) films were deposited by electron beam excited plasma (EBEP) CVD. As the SiH4 flow rate increases, deposition rate steeply increases, however, crystalline fraction and grain size decrease. A high deposition rate of 69 nm/min is achieved using SiH4 without H2 dilution. It is shown that H atom plays key roll for μc-Si:H formation. Results show that deposition mechanism of μc-Si:H by EBEP is mainly controlled by the reaction in the plasma rather than the reaction on the film surface.