Mechanical film deposition

Mechanical Film Deposition - In this technique, a doctor blade is used to mechanically deposit a thin film (usually particles in a liquid matrix) upon a surface as shown in the following diagram ... 

Epitaxial crystal growth methods such as molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD) have advanced to the point that active regions of essentially arbitrary thicknesses can be prepared (see Thin films, film deposition techniques). Most semiconductors used for lasers are cubic crystals where the lattice constant, the dimension of the cube, is equal to two atomic plane distances. When the thickness of this layer is reduced to dimensions on the order of 0.01 )J.m, between 20 and 30 atomic plane distances, quantum mechanics is needed for an accurate description of the confined carrier energies (11). Such layers are called quantum wells and the lasers containing such layers in their active regions are known as quantum well lasers (12). 

The kinetics and mechanism of this reaction have been studied for years on Pt films deposited on doped Zr02.15 It has been found that at temperatures above 280°C the open-circuit catalytic kinetics can be described quantitatively by the rate expression... 

Figure 11.7. XPS confirmation of O5 backspillover as the mechanism of electrochemical promotion on Pt films deposited on YSZ (a) and on Ti02 (b). Adapted from refs.31,32. In both cases A is the open-circuit Ols spectrum, B is the 01 s spectrum under anodic (I>0, AUWr>0) polarization and C is the difference spectrum.22,31,32 Reprinted with permission from the American Chemical Society (a, ref. 32) and from Academic Press (b, 31).

Figure 11.7 confirms that electrochemically induced and controlled O2 backspillover from the support to the metal film surface is the promoting mechanism both in the case of YSZ (Fig. 11.7a) and in Ti02 (Fig. 11.7b). These figures show the Ols spectrum of the Pt film deposited on YSZ and on TiC>2, first under open-circuit conditions (Fig. 11.7aC, 11.7bA) and then under positive current and potential application (Fig. 11.7aB, 11.7bB). Figures 11.7aC and 11.7bC show the difference spectra. In both cases, XPS clearly shows the presence of the O2 double layer, even under open-circuit conditions (Figs. 11.7aA, 11.7bA) and also clearly confirms the electrochemically controlled backspillover of O2 from the YSZ orTi02 support onto the catalyst surface. Note that the binding energy of the backspillover O species is in both cases near 529 eV, which confirms its strongly anionic (probably O2 ) state.31,32...

Popov, C., Zambov, L. M., Plass, M. R, and Kulisch, W., Optical, Electrical and Mechanical Properties of Nitrogen-rich Carbon Nitride Films Deposited by Inductively Coupled Plasma Chemical Vapor Deposition," Thin Solid Films, Vol. 377-378,2000, pp. 156-162. 

Planarization- Chemical mechaniced planjurization machines are used to level the topology of the films deposited on the wafer. Chemical-mechanical smoothing is the process used to improve process uniformity, repeatability, removal rate, planarity and defeet reduction. Thus, planarization is requisite to producing defect-free CMOS circuits. 

Laser ablation of polymer films has been extensively investigated, both for application to their surface modification and thin-film deposition and for elucidation of the mechanism [15]. Dopant-induced laser ablation of polymer films has also been investigated [16]. In this technique ablation is induced by excitation not of the target polymer film itself but of a small amount of the photosensitizer doped in the polymer film. When dye molecules are doped site-selectively into the nanoscale microdomain structures of diblock copolymer films, dopant-induced laser ablation is expected to create a change in the morphology of nanoscale structures on the polymer surface. 

J. O. (2001) Spontaneous potential oscillations in the Cu(II)/tartrate and lactate systems, aspects of mechanisms and film deposition. J. Electrochem. Soc., 148, C513-C517. 

The reactions taking place at the growing surface of plasma-deposited a-C H were reviewed by Jacob [29], and from this discussion emerged a framework to understand the a-C H film deposition mechanism. This framework is to some extent equivalent to the subplantation model, since it emphasizes the role of energetic molecular ions. In addition, it takes into account the role of neutral radicals. 

FIG. 37. Internal stress and mechanical hardness as functions of nitrogen content, and for films deposited from aC2H2-N2 mixture. (Reproduced from [56].)... 

Several research groups21-23 suggested the following mechanism for CBD CdS film deposition, where Cd(OH)2 species assist the film growth ... 

When argon was used as a carrier gas to deposit PNT-N film at 10 Torr, amorphous PNT-N film was obtained but the mechanical properties of the film as deposited were inferior to the film deposited at 0.45 Torr without a carrier gas. 

Polycondensation, 10 189-190, 191 as an aging mechanism, 23 64 of polyamide plastics, 19 781-782 polyester formation by, 20 390-391 silicone polymerization via, 22 556-558 in the sol-gel process, 23 61-62 Polycrystalline alloys, 13 523 Polycrystalline diamond films, deposition of, 24 744-745... 

Fig. 12.3 Fabrication of the nanocomposite paper units for battery, (a) Schematic of the battery assembled by using nanocomposite film units. The nanocomposite unit comprises LiPF6 electrolyte and multiwalled carbon nanotube (MWNT) embedded inside cellulose paper. A thin extra layer of cellulose covers the top of the MWNT array. Ti/Au thin film deposited on the exposed MWNT acts as a current collector. In the battery, a thin Li electrode film is added onto the nanocomposite, (b) Cross-sectional SEM image of the nanocomposite paper showing MWNT protruding from the cel-lulose-RTIL ([bmlm] [Cl]) thin films (scale bar, 2pm). The schematic displays the partial exposure of MWNT. A supercapacitor is prepared by putting two sheets of nanocomposite paper together at the cellulose exposed side and using the MWNTs on the external surfaces as electrodes, (c) Photographs of the nanocomposite units demonstrating mechanical flexibility. Flat sheet (top), partially rolled (middle), and completely rolled up inside a capillary (bottom) are shown (See Color Plates)...

Figure 3.16 Different steps in the fabrication of MWNT nanoelectrode arrays, (a) metal film deposition, (b) catalyst deposition, (c) plasma-enhanced chemical vapor deposition for CNT growth, (d) dielectric encapsulation with Si02, (e) planarization with a chemical mechanical polishing to expose the ends of the carbon nanotubes, (f) electrochemical characterization. Readapted from Ref [6].

Yubero, F. Gonzalez-Elipe, A.R. Tougaard, S. (2000) Determination of growth mechanisms by x-ray photoemission and ion scattering spectroscopies Application to thin iron oxide films deposited on Si02. Surface Sci. 457 24-36... 

It will be obvious that the cluster mechanism of deposition is unlikely to lead to an oriented film, since the clusters would have to align themselves with the substrate lattice, either on adsorption or subsequently. Therefore an epitaxial film is highly suggestive of an ion-by-ion growth, which is more likely to be directed by the substrate. 

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