Pt-coated silicon substrates

Stresses produced in sol-gel-derived films modify the lattice parameters of the film and its orientation or texture. These effects are clearly observed in the X-ray diffraction (XRD) patterns of Figure 27.16 [55]. The XRD pattern of a (Ca, Pb) TiOs perovskite thin film on a Pt-coated silicon substrate shows a textured film with a (100) preferred orientation and with the cell parameters for the perovskite indicated in Table 27.5. When this film is electrolytically separated from the substrate, it recovers the random orientation of the ceramic powder and its preferred orientation disappears observe the lattice parameters and strains measured in a (Ca, Pb)TiOs thin film on the substrate and this film is separated from the substrate in comparison with those of the bulk ceramic (Table 27.5) [55]. 

Table 27.5 Lattice parameters of the perovskite calculated from the experimental XRD patterns of the (Ca, PbjTiOs thin film on a Pt-coated silicon substrate and on this film electrolyti-...

Figure 27.23 Some methods of obtaining nanostructures from sol-gel solutions, (a-c) Microstructural instability method showing how a thin film breaks into islands for a grain size to film thickness ratio. Images correspond to cross-sectional TEM photographs of films with different thickness. (Reprinted with permission from Ref. [62].) (d-f) Microemulsion-mediated synthesis method showing a scheme with the preparation method to obtain an array of nanostructures on polycrystalline Pt-coated silicon substrates. A micellar solution containing the building units...

The (100) orientation has been found to produce large dielectric constant and high tunability [44,56]. BST films have been successfully fabricated on Pt coated silicon substrates by sputtering [56], chemical vapor deposition (CVD) [57], and pulsed laser deposition (PLD) [58]. Compared to other deposition methods, the sputtering process offers some special characteristics, for example, controlling the Ar/02 ratio and the total (Ar + O2) pressure during the deposition could attain the (100) preferred orientation [56] and adjust the... 

A third way to build up pFCs based on MEMS-polymers such as poly-dimethylsiloxane (PDMS) or polymethyl methacrylate (PMMA) or PCB-materials such as polyimid (PI) or FR4. These polymers can be micro-machined by molding or by laser ablation. Shah et al. [22,23] have developed a complete PEMFC system consisting of a PDMS substrate with micro-flow channels upon which the MEA was vertically stacked. PDMS micro-reactors were fabricated by employing micro-molding with a dry etched silicon master. The PDMS spin coated on micro-machined Si was then cured and peeled off from the master. The MEA employed consisted in a Nafion - 12 membrane where they have sputtered Pt through a Mylar mask. Despite an interesting method, this FC gave poor results, a power density of 0.8 mW cm was achieved. 

Uses Flow aid, substrate wetting agent for waterborne coatings Features Silicone-free no effect on recoat adhesion Properties Yei. clear Iiq. dens. 1.04 g/cm (20 C) dynamic vise. 350-520 mPa s flash pt. 50 C pH 8-9.5 (10%) 50% act. 

Uses Wetting agent for polymer disps., mech. processes, aq. paints/ coatings, printing inks, emulsions, adhesives, difficult substrates e.g., plastic and metal surfs., cellophane and plastic films, aluminum foil, silicone-treated papers, glass, aq. overprint varnishes of offset prints Features Compat. in different polymer systems Properties Water-wh. clear liq. sol. in water vise. 50-150 mPa-s set pt. 

Instruments and Materials. The silicon wafers were obtained from Wafemet Incorporated. Si (100) surfaces were used in these studies and the wafers were p-type silicon with tolerances and specifications as per SEMI Standard M1.1.STD.5 cut to the approximate dimensions 10 x 12 mm as needed. The substrates used for PZT deposition were Si(l 11) wafers coated with 1000 A of titanium and 2000 A of Pt(l 11). These wafers were prepared and donated by Northern Telecom Canada. 

Fig. 2 Process flow (a) Starting Material, (b)Deposit SisN (c)Deposit poly-silicon, (d) Deposit Al, (e) Resist coating, (f) Soft bake, (g) Exposure mask, (h) Develop resist (i) Poly-silicon RIE, (j) Alum etch and stripe resist, ion(k) Dry oxidation, (1) Poly-silicon nanogap pattern with pad Pt/Au fabrication( Electrical checking of the device can be performed on the fabricated pad)(Repeat step (a) to (j) for mask 2). Fig. 3 shows the circuit after serial impedance is measured, a simple resistor model is developed representing the substrate and polysilicon layer. The capacitor also found in series to describe the device with no liquid test...

Uses Defoamer for aq. formulations, printing inks, adhesives, industrial maintenance coatings, wood coatings, latex dipping bath formulations Features Esp. suitable for applic. to porous substrates silicone-free Properties Tan liq. self-emulsiflable in water sp.gr. 0.912 vise. < 600 cps vapor pressure 10 mm Hg (21 C) m.p. -7 C pour pt. < 2 C flash pt. (PMCC) HOC VOC 4.8% 100% act. 

Uses Substrate wetting agent for aq. and solvent-based coatings, printing inks, wood and furniture applies, (spray- and roller-applied), industrial/domestic appliance coatings, overprint varnishes, silicone-polyester based heat-resist, coatings, aq, primers for plastics, water-borne fillers for automotive coatings Properties Sp.gr. 1.00-1.02 dens. 8.5 Ib/gal vise. 40-90 mPa-s flash pt. > 150 C ... 

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