Chemical solution deposition

Gorer S, Hodes G (1994) Quantum size effects in the study of chemical solution deposition mechanisms of semiconductor films. J Phys Chem 98 5338-5346... 

Chemical solution deposition (CSD) procedures have been widely used for the production of both amorphous and crystalline thin films for more than 20 years.1 Both colloidal (particulate) and polymeric-based processes have been developed. Numerous advances have been demonstrated in understanding solution chemistry, film formation behavior, and for crystalline films, phase transformation mechanisms during thermal processing. Several excellent review articles regarding CSD have been published, and the reader is referred to Refs. 5-12 for additional information on the topic. Recently, modeling of phase transformation behavior for control of thin-film microstructure has also been considered, as manipulation of film orientation and microstructure for various applications has grown in interest.13-15... 

Figure 2.1. Processing stages in chemical solution deposition of thin films. Controllable parameters are shown on the left dependent processes are shown in italics. [Reprinted from Ref. 16 with the permission of the publisher, Taylor Francis, Ltd. R. W. Schwartz et al., Sol-gel processing of PZT thin films a review of the state-of-the-art and process optimization strategies, Int. Ferro., 7,259, (1995).]...

Figure 2.2. Classes and examples of common metallo-organic starting compounds used in chemical solution deposition processing. A common feature for all compounds is M-O-C bonding. Associated structures are also shown. [Adapted with permission from Ref. 8 R. W. Schwartz et al., C. R. Chemie, 7, 433 (2004).]...

TABLE 2.1. Summary of the Principal Chemical Solution Deposition Methods... 

Over the course of the past 20-25 years, hundreds of studies on the fabrication of electronic thin hlms by chemical solution deposition methods have been reported. Because previous review articles have focused on summarizing the results of these investigations, they are not considered in detail here, but rather a more general approach to him formation and subsequent structural... 

TABLE 2.5. Characterization Methods Used in Chemical Solution Deposition Processing... 

Schneller, T. Waser, R. 2002. Chemical solution deposition of ferroelectric thin films—state of the art and recent trends. Ferro. 267 293-301. 

Schwartz, R. W. 1997. Chemical solution deposition of perovskite thin films. Chem. Mat. 9 2325-2340. 

Kotzyba, G. Obst, B. Nast, R. Goldacker, W. Holzapfel, B. 2006. Chemical solution deposition (CSD) of Ce02 and La2Zr207 buffer layers on cube textured NiW substrates. J. Phys Conf. Ser. 43 345-348. 

Schwartz, R. W. Reichert, T. L. Clem, P. G. Dimos, D. Liu, D. 1997. A comparison of diol and methanol-based chemical solution deposition routes for PZT thin film fabrication. Int. Ferro. 18(l-4) 275-286. 

Brennecka, G. Tuttle, B. 2007. Deposition of ultrathin film capacitors fabricated by chemical solution deposition. /. Mat. Res. 22 2868-2874. 

Hoffmann, M. Hofer, C. Schneller, T. Bottger, U. Waser, R. 2002. Preparation and aging behavior of chemical-solution-deposited (Pb(Mg1/3Nb2/3)03)i x-(PbTi03)x thin films without seeding layers. J. Am. Ceram. Soc. 85 1867-1869. 

Hoffmann, S. Haxenkox, U. Waser, R. Jia, J. L. Urban, K. 1997. Chemical solution deposition of BaTi03 and SrTi03 with columnar microstructures. In Science and Technology of Semiconductor Surface Preparation, edited by Hagashi, G. S. Hirose, M. Ragahavan, S. Verhaverbeke, S. Mat. Res. Soc. Symp. Proc. 477 9-14. 

Kobayashi, T. Ogawa, R. Miyazawa, K. I. Kuwabara, M. 2002. Fabrication of beta -BaB204 thin films with (001) preferred orientation through the chemical solution deposition technique. J. Mater. Res. 17 844-851. 

H. Tomonaga and T. Morimoto, Indium-tin oxide coatings via chemical solution deposition, Thin Solid Films, 392 243-248 (2001). 

Chemical shim control, in nuclear power facilities, 17 544 Chemical shippers, 25 324 Chemical sludge, 25 912 Chemical solution(s) deposition from, 23 13 thin films from, 24 747—750 Chemical solution deposition, 23 13 as fabrication method for inorganic materials, 7 415t Chemical space, 6 16... 

Chemical solution deposition (CSD) known also as chemical bath deposition (CBD) and simply chemical deposition (CD, the form we will use in this book) was first described in 1869, and it has been nsed since to deposit films of many different semiconductors. It is probably the simplest method available for this purpose—all that is needed is a vessel to contain the solntion (an aqueous solution made np of a few, usually common, chemicals) and the snbstrate on which deposition is reqnired. Various complications, snch as some mechanism for stirring and a thermostated bath to maintain a specific and constant temperature, are options that may be nsefnl. 

The CD technique is based on either slow formation of a reactive anion or slow decomposition of a complex compound. However, there are other techniques, not involving these slow steps, that nevertheless are sometimes called chemical deposition or chemical solution deposition or are closely related. These techniques are dealt with very briefly in this section. 

Very acidic (high valent) cations will readily hydrolyse in aqueous solution, often even at low pH. These cations tend to form the polymeric metal oxide chains mentioned previously. This hydrolysis can be controlled by addition of boric acid (see Sec. 3.2.4.4) and forms the basis of a technique referred to as liquid phase deposition. This method can be reasonably included in the more general term of chemical solution deposition, and is treated, although not comprehensively, in this book. Ref 5 deals more thoroughly with this technique and describes many cases of SiOi as well as some examples of several other oxides not covered in this chapter. 

For this study pzt films with (111) and (100) orientation grown on Pt (111) bottom electrodes by chemical solution deposition were used. In the case of (100) orientation a 10 nm lead titanate buffer layer was used in order to enhance (100) nucleation. The films with Zr/Ti ratio of 40/60 contained dopants including Ca, Sr and La [20]. The thickness of (111) and (100) oriented films was 135 nm and 150 nm, respectively. IrCL top electrodes with different sizes down to 0.5x 0.5 pm2 have been patterned by reactive ion etching. The electroded pzt film was etched approximately to a half of its original thickness. 

The sol-gel process is a wet-chemical technique (chemical solution deposition) widely used recently in the fields of materials science and ceramic engineering. Such methods are used primarily for the fabrication of materials (typically a metal oxide) starting from a chemical solution which acts as the precursor for an integrated network (or gel) of either discrete particles or network polymers. Typical precursors are metal alkoxides and metal chlorides, which undergo various forms of hydrolysis and polycondensation reactions. 

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