Films deposition methods

After the precursor stock solution is prepared, various techniques can be used to coat the substrate, depending on the solution viscosity, required film thickness and coverage. The most common methods in the semiconductor industry are spin- and dip-coating. Other processes that are used for deposition include spray coating and stamping. A summary of the uses, limitations, and advantages of the various thin film deposition methods is reported in Table 2.2. 

In the short term, there is a need to reduce the cost of thin-film solar cells. To do this will require the development of deposition techniques of thin films such as microcrystalline silicon and other materials that are robust and provide high throughput rates without sacrificing film efficiencies. In the short run, thin-film deposition methods can potentially gain... 

The flush of speed affected substantially the HTE community during the first years. Speed is still an issue of concern. Pioneering technologies like thin film deposition by sputtering of compounds using masks has been developed by Hanak [3] and brought to perfection by Symyx [4]. Additiomlly, other film deposition methods have been adapted to caMyst syntheses like thermal and... 

In a recent review, it was reported that H2S was determined with crystals coated using the Langmuir-Blodgett film deposition method (44). Linear responses over the concentration range O-lOO ppm using uTA and ttbPcSiClz coatings. 

Electrochemical atomic layer epitaxy (EC-ALE) is the combination of underpotential deposition (UPD) and ALE. UPD is the formation of an atomic layer of one element on a second element at a potential under, or prior to, that needed to deposit the element on itself [5, 6]. The shift in potential results from the free energy of the surface compound formation. Early UPD studies were carried out mostly on polycrystalline electrode surfaces [7], This was due, at least in part, to the difficulty of preparing and maintaining single-crystal electrodes under well-defined conditions of surface structure and cleanliness [8]. The definition of epitaxy is variable but focuses on the formation of single crystal films on single crystal substrates. This is different from other thin film deposition methods where polyciystalline or amorphous film deposits are formed even on single crystal substrates. Homoepitaxy is the formation of a compound on itself. Heteroepitaxy is the formation of a compound on a different compound or element and is much... 

Immersion 2. Start-up 3. Deposition Figure 12.11 Dip-coating film deposition method. 

Film electrodes In contrast to the chemical etching methods, the film deposition method adds atoms at the substrate to form a rough film and/or discontinuous islands. This technique is commonly adapted from prior work in surface science and often realized in UHV chambers. However, the deposited film electrode is unlikely to have the same crystalline structure as the bulk metal phase formed by metallurgy that is usually used in electrochemistry. Moreover, film electrodes exhibit relatively poor surface stability and electrochemical re-versibiKty, particularly if the experiment is conducted over a wide potential region. 

A final important motif for self-assembly of CPEs is by LbL deposition of polyelectrolyte multilayer films. The LbL multilayer film deposition method was first introduced by Decher [37,38], and since then it has been used to fabricate nanostructured films using a wide variety of synthetic and naturally occurring polyelectrolytes [39]. Deposition of LbL films involves a very simple sequence of alternately dipping a substrate into solutions that contain a cationic polyelectrolyte and an anionic polyelectrolyte. The sequential LbL deposition method leads to formation of polymer multilayer film structures. A single... 

CVD is a well-understood thin film deposition method that uses chemical reactions of vapor-phase precursors. CVD processes have traditionally been initiated and controlled by heat as the source of energy. An elevated deposition temperature is normally required, which restricts the types of substrates that can be used and coating materials that can be deposited, especially thermally sensitive ones (Jones and Hitchman, 2009). However, thermal energy is not the only energy supplied to the system plasmas and photons are widely used in CVD processes. Plasma-enhanced chemical vapor deposition (PECVD), or plasma-assisted CVD, is a CVD technique in which plasma in lieu of thermal energy is used primarily to activate ions and radicals in the chemical reactions leading to layer formation on the substrate. One major advantage of PECVD over... 

Thin film deposition methods based on gas-phase processes such as CVD, evaporation, and sputtering are straightforward and thin films with good purity and structural properties can be produced. However, there are some drawbacks, such as the strict instrumentation requirement, relatively high processing cost, as well as gaseous waste treatment. In comparison, chemical and electrochemical solution methods are cost-effective and waste is confined to the solution. 

Molecular beam epitaxy (MBE) is a thin film deposition method with exceptional control over the deposit growth. It is the author s contention that there are no fundamental reasons why electrodeposition cannot achieve a similar degree of control. 

Figure 3 shows a somewhat idealized process flow. It starts with the blanket deposition of material A by virtually any thin film deposition method onto a substrate (a). The sample is then coated with photoresist, which is exposed (b) and developed (c). The photoresist masking... 

Agnew J (1973) Thick film technology fundamentals and applications in microelectronics. Hayden, RocheUe Park, NJ Bakrania SD, Wooldridge MS (2009) The effects of two thick film deposition methods on tin dioxide gas sensor performance. Sensors 9 6853-6868... 

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