Ceramic Thin Films

Solution Deposition of Thin Films. Chemical methods of preparation may also be used for the fabrication of ceramic thin films (qv). MetaHo-organic precursors, notably metal alkoxides (see Alkoxides, metal) and metal carboxylates, are most frequently used for film preparation by sol-gel or metallo-organic decomposition (MOD) solution deposition processes (see Sol-GEL technology). These methods involve dissolution of the precursors in a mutual solvent control of solution characteristics such as viscosity and concentration, film deposition by spin-casting or dip-coating, and heat treatment to remove volatile organic species and induce crystaHhation of the as-deposited amorphous film into the desired stmcture. 

Diamond and Refractory Ceramic Semiconductors. Ceramic thin films of diamond, sihcon carbide, and other refractory semiconductors (qv), eg, cubic BN and BP and GaN and GaAlN, are of interest because of the special combination of thermal, mechanical, and electronic properties (see Refractories). The majority of the research effort has focused on SiC and diamond, because these materials have much greater figures of merit for transistor power and frequency performance than Si, GaAs, and InP (13). Compared to typical semiconductors such as Si and GaAs, these materials also offer the possibiUty of device operation at considerably higher temperatures. For example, operation of a siUcon carbide MOSFET at temperatures above 900 K has been demonstrated. These devices have not yet been commercialized, however. 

Niesen, T. R De Guire, M. R. 2001. Review Deposition of ceramic thin films at low temperatures from aqueous solutions. J. Electroceram. 6 169-207. 

Membrane Ceramic, polypropylene (PP), Thin film of ceramic. Thin film of CA Thin film of CA... 

M. Sayer and K. Sreenivas, Ceramic thin films fabrication and applications. Science 247, 1056-1060 (1990). 

Sayer, M. and K. Sreenivas "Ceramic Thin Films Fabrication and Applications, ... 

Keywords ceramic thin films, titania, polyimides, polymer matrix composites 1. Introduction... 

LPD deposition of ceramic thin films is a potentially general approach to improving the abrasion resistance and thermo-oxidative stability of polymers. Dutschke et al.14,15 have deposited titania on variously treated polystyrene (PS). Continuous, adherent anatase films form on PS either after hydroxylation in... 

Alkoxides. These are among the most useful complexes one application is the production of ceramic thin films.31 They are made by reactions such as... 

In the last several years, polymer thin film deposition using chemical vapor deposition (CVD) has become increasingly popular. CVD of polymers offers numerous unique advantages over other polymer synthesis techniques and has been exploited for a multitude of applications in microelectronics, optical devices, biomedical industry, corrosion resistant and protective coatings, and even in the automobile industry. CVD of polymers (also referred to as chemical vapor polymerization, CVP, or sometimes Vapor Deposition Polymerization, VDP) differs from inorganic CVD (such as for metallic or ceramic thin films) and must be developed and optimized... 

Functional ceramic thin films have been used in a variety of electronic devices. In particular, Si02 thin films are widely used for device passivation and protection of magnetic and optical disks. The synthesis of Si02 thin films can be conveifiently... 

Bunker, B. C., et al. (1994) Ceramic Thin-Film Formation on Functionalized Interfaces Through Biomimeting Processing, Science 264, 48-55. 

The reactivity of the four-membered ring heterocyclic molecule Cp2Ti(GH2SiMe2NSiMe3) as a single-source precursor to titanium-based ceramic thin films has been studied under atmospheres of nitrogen, argon, and... 

G.L., Song, L., Liu, J., Virden, J.W., and McVay, G.L. (1994) Ceramic thin-film formation on functionalized interfaces through biomimetic processing. Science, 264 (5155), 48-55. 

IONIC CONDUCYIVITY OF NANOCRYSTALLINE YSZ CERAMIC THIN FILMS... 

Why are we interested in this topic Ceramic thin films are becoming increasingly important in the electronics industry for their novel magnetic and electrical properties. Often these films are neither amorphous nor single crystal, so GBs become relevant. There will be TJs in the film and at the substrate/film interface (even if the substrate is amorphous). The TJ can form a pit (a 3D groove) at the surface, but it will generally not groove at the substrate. 

There are four general characteristics that we usually want to control when growing ceramic thin films ... 

From the above discussion you can see that there are several stringent requirements for ceramic thin films. For this reason, there are numerous techniques that have been used to form such films. Some techniques work better for some materials whereas other techniques work better for other materials. We describe some of the techniques used to form ceramic thin films in the following sections, but this is not a comprehensive list. 

Chemical compatibility. There should be no deleterious reactions between the film and the substrate. For the high temperatures (>700°C) used during the growth of many ceramic thin films this requirement may be quite restrictive. 

Lattice mismatch. In semiconductor systems lattice mismatches of only a few percent, or less, are desired to reduce the number of dislocations in the film. In ceramic thin films larger mismatches (generally <15%) are tolerated because higher defect densities in the film are acceptable. In some situations a certain number of defects are actually beneficial to film properties (they can provide piiming sites in high-temperature superconductors that can trap magnetic flux lines). 

What reactive gases would be suitable for forming the following ceramic thin films by reactive sputtering ... 

Most ceramics have very high Tb. Consequently their vapor pressures are negligible at room temperature and become appreciable only at high temperature. Also very few ceramics vaporize without a molecular change. The result is that the vapor composition is usually not the same as that of the original liquid or solid. A practical consequence is that when we try to grow ceramic thin films by evaporation as described in Chapter 28 the film may have a stoichiometry different from that of the source. Some of the phenomena that can occur when compounds evaporate are shown in Table 34.5. 

Figure 9.8 Reprinted from Susnitzky D.W. and Carter, C.B. (1992) Surface morphology of heat-treated ceramic thin films, J. Am. Ceram. Soc. 75, 2471, with permission from Blackwell Publishing and the American Ceramic Society.

Up to now, polymer pyrolysis has been investigated especially to develop ceramic fibers [46,47] and ceramic matrix for ceramic matrix composites [48-50]. More recently studies have been undertaken to exploit this method to develop ceramic thin films [51-53], foams [54], joints [55], and bulk materials [56]. Moreover, noncon-ventional heating systems such as laser [57], microwave heating [53], or even athermal conversion processes such as ion bombardment are just now starting to be applied to the polymer route and the preliminary results are very promising [58-60]. In this chapter we focus on the polymer processing of bulk ceramics obtained by pyrolysis of partially cross-linked preceramic bodies and of thin ceramic films (obtained either by traditional pyrolysis or by the innovative ion irradiation process). 

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