I. Doi

Bio: I. Doi is an academic researcher from State University of Campinas. The author has contributed to research in topics: Ellipsometry & Thin film. The author has an hindex of 10, co-authored 23 publications receiving 360 citations.

Highly stable hydrophilic surfaces of PDMS thin layer obtained by UV radiation and oxygen plasma treatments

Abstract: Surface modification of polydimethylsiloxane (PDMS, Sylgard 184) was carried out by O2 plasma and UV in broadband mode/O2 plasma treatments with different exposure times, and studied in terms of hydrophilic stability. Water contact angle measurements, Fourier Transform Infrared Spectroscopy (FTIR) and Atomic Force Microscopy (AFM) were used for the analysis of the modified surface and hydrophilic stability of the PDMS films. The results show reasonably good hydrophilic stability in the range of a week with a contact angle of around 70° for O2 plasma treated samples, whereas a more high hydrophilic stability, with a low contact angle of 65° up to 15 days, was observed for UV/O2 plasma treated PDMS. FTIR analysis of the samples reveals significant oxidation noted by large presence of Si-O-Si, and Si-OH bonds on the PDMS surface, which improves the affinity with water molecules and increases the hydrophilicy. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Micro-Raman stress characterization of polycrystalline silicon films grown at high temperature

Abstract: In this paper the residual stress of polycrystalline silicon (poly-Si) grown at high temperature in a vertical LPCVD reactor has been studied using micro-Raman spectroscopy. The samples were prepared on Si(1 0 0) n-type substrates coated with 100 nm of SiO2. The films were deposited in the temperature range of 750–900 °C at pressures of 5 and 10 Torr. The as-deposited poly-Si films are highly crystalline and show tensile stress. Micro-Raman measurements show that the residual stress is reduced as the deposition temperature is increased and, above 800 °C, tensile stress is reduced to less than 150 MPa. These results indicate that high quality, high crystalline and low strained poly-Si films can be obtained in this type of reactor using higher deposition temperature.

Electromagnetic properties of Si–C–N based ceramics and composites

Abstract: Besides the excellent high-temperature mechanical properties, Si3N4 and SiC based ceramics containing insulating or electrically conductive phase are attractive for their tunable dielectric propert...

Oxygen and nitrogen plasma hydrophilization and hydrophobic recovery of polymers

Abstract: Plasma hydrophilization and subsequent hydrophobic recovery are studied for ten different polymers of microfabrication interest: polydimethylsiloxane (PDMS), polymethylmethacrylate, polycarbonate, polyethylene, polypropylene, polystyrene, epoxy polymer SU-8, hybrid polymer ORMOCOMP, polycaprolactone, and polycaprolactone/D,L-lactide (P(CL/DLLA)). All polymers are treated identically with oxygen and nitrogen plasmas, in order to make comparisons between polymers as easy as possible. The primary measured parameter is the contact angle, which was measured on all polymers for more than 100 days in order to determine the kinetics of the hydrophobic recovery for both dry stored and rewashed samples. Clear differences and trends are observed both between different polymers and between different plasma parameters.

Si-containing film forming precursors and methods of using the same

Abstract: Mono-substituted TSA precursor Si-containing film forming compositions are disclosed. The precursors have the formula: (SiH3)2N—SiH2—X, wherein X is selected from a halogen atom; an isocyanato group; an amino group; an N-containing C4-C10 saturated or unsaturated heterocycle; or an alkoxy group. Methods for forming the Si-containing film using the disclosed mono-substituted TSA precursor are also disclosed.