文档介绍：9
Thin Film Deposition Processes for
Electronic and Structural Ceramics
t *
R. C. Budhani and R. F. Bunshah
* Department of Materials Science and Engineering,
University of California, Los Angeles, Los Angeles,
California 90024-1595, USA.
t Brookhaven National Laboratory, Upton, New York
11973, USA.
1. INTROWCTION
Ceramic materials, depending on their electrical conductivity, can be
broadly classified as metallic and non-metallic. The metallic ceramics
prise pounds of transition metals with the elements of
group III, IV and V of the periodic table,, carbon, silicon and
nitrogen, thus constituting the borides, carbides, silicides and nitrides.
The metal 1 ic character in these systems arises because of the intermixing
between s-p electrons of the non-metals and d electrons of the transition
metal. Apart from their high electrical conductivity, this class of ceramics
is also characterized by high melting point, extreme hardness and relative
imunity to chemical corrosion and oxidation. Furthermore, their relatively
close packed structure makes them less susceptible to diffusion of foreign
atoms through them. bination of these properties have made this class
of materials very useful in a variety of structural and electronic
applications.
The other class of ceramics consists of the oxides of various elements
and pounds involving two elements whose electronic character is
decided by s-p electrons only. Excluding some transition metal oxides, most
of pounds are electrically insulating. The predominantly insulating
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370 Advanced Ceramic Processing and Technology
character arises from the strong chemical bonding between the constituents
and the mixed ionic-covalent character of the bonds. The wide band gap
resulting from such bonding provides these materials their characteristic
transparency in the visible and near UV regions of the ic
spectrum. The wide band gap can be modulated v