Thin-film deposition studies

Several years later, Kanatzidis et al. reported the preparation of hetero-binuclear complexes of tetrahedrally arranged Cu and In centers, with two bridging thiolato or selenolato groups, [ PPh3 2Cu(p-QEt)2In(SEt)2], (Q = S or Se) (i.e., equation 6.3).38 Pyrolysis studies undertaken revealed that the Se derivative could be converted into CuInSe2 at 400-450 °C at 0.01 mm Hg (see equation 6.4). However, none of the precursors had been evaluated in a thin-film deposition study. 

Thermogravimetry and pyrolysis studies at 300 °C, (O.SinmHg) for 30 min revealed that these compounds decompose to give the corresponding ternary metal sulfide materials, but thin-film deposition studies for the Ga derivatives are yet to be studied. 

The following two sections will focus on epitaxial growth from a surface science perspective with the aim of revealing the fundamentals of tliin-film growth. As will be discussed below, surface science studies of thin-film deposition have contributed greatly to an atomic-level understanding of nucleation and growth. 

The thermal decomposition of silanes in the presence of hydrogen into siUcon for production of ultrapure, semiconductor-grade siUcon has become an important art, known as the Siemens process (13). A variety of process parameters, which usually include the introduction of hydrogen, have been studied. Silane can be used to deposit siUcon at temperatures below 1000°C (14). Dichlorosilane deposits siUcon at 1000—1150°C (15,16). Ttichlorosilane has been reported as a source for siUcon deposition at >1150° C (17). Tribromosilane is ordinarily a source for siUcon deposition at 600—800°C (18). Thin-film deposition of siUcon metal from silane and disilane takes place at temperatures as low as 640°C, but results in amorphous hydrogenated siUcon (19). 

Venkatasamy V, Mathe MK, Cox SM, Happek U, Stickney JL (2006) Optimization studies of HgSe thin film deposition by electrochemical atomic layer epitaxy (EC-ALE). Electrochim Acta 51 4347-4351... 

Studies of the dependence of deposit structure on cycle conditions are continuing. Most of the work along this line has been performed with CdTe [311]. Optimizations of CdSe and CdS are continuing as well and look promising [321]. That is, it appears that significant improvements in deposit structure will be possible. Studies of this type with most of the compounds mentioned above represent the bulk of the studies needed to answer the questions raised at the beginning of this section. These studies involve the formation of thin film deposits under systematically varying conditions followed by characterization. 

With materials of this type FIM finds its limitations. Several attempts have been made to use field ion microscopy to study amorphous materials such as metallic glasses and amorphous silicon or hydrogenated amorphous silicon thin films deposited on metal tip surfaces.96"98 100-102 Since there is no well defined crystal lattice, the structure of an amorphous material is usually described by the pair distribution function of the... 

The main physicochemical processes in thin-film deposition are chemical reactions in the gas phase and on the film surface and heat-mass transfer processes in the reactor chamber. Laboratory deposition reactors have usually a simple geometry to reduce heat-mass transfer limitations and, hence, to simplify the study of film deposition kinetics and optimize process parameters. In this case, one can use simplified gas-dynamics reactor such as well stirred reactor (WSR), calorimetric bomb reactor (CBR, batch reactor), and plug flow reactor (PFR) models to simulate deposition kinetics and compare theoretical data with experimental results. 

Fig. 3 Different synthesis techniques studied for parylene thin film deposition. ...

A study of dielectric characteristics of alumina thin films deposited on silicon substrates from Al(acac)3 dissolved in dmf by spray pyrolysis between 450 and 650 °C was recently reported by Falcony and coworkers. The addition of water vapor significantly improved the dielectric characteristics and smoothness of the deposits. In comparison to the CVD technique described above (see Section m.A.l) this procedure lead to considerable carbon impurities in the films. The overall resisfivify of fhe alumina layers decreases, when both the concentration of the solution and the deposition temperature increase, which is explainable with the increase of carbon residues in the films. 

Polypyrrole (PPy) has been studied in the form of thin films deposited on electrode surfaces, by electrochemical oxidative polymerization of pyrrole with anions (e.g. C104, HSO4 ) present in solution, resulting in relatively air-stable, highly conducting films. Chemical oxidation of pyrrole with Cu(II) or Fe(III) salts in solution has also been reported.58,59,60,61... 

PDlyiiier thin films deposited in an rf electrical discharge have been suggested for use as dielectric materials in electrical capacitors As a preliminary step toward the study of the... 

In another study, Heidberg et al. [68] investigated CO and COj adsorption under ultrahigh vacuum conditions on C g thin films deposited on KBr(lOO). The IR spectra were recorded at different polarizations. The results obtained with both adsorption systems again point to the existence of two different adsorption sites on the C q film. The spectra showed different absorption intensities depending on the type of polarization. This was interpreted by the authors as being due to the anisotropy of the Cgg film. 

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