THERMAL CVD of Dielectrics and Semiconductors

In the present chapter, we will turn our attention to films deposited by thermal CVD that are either dielectrics or semiconductors. There are, as one would expect, many films that can be deposited by this technique. In addition, there are many gaseous reactants that one can use to create each film, the choice depending on the film characteristics desired. Rather then attempt to catalogue all of the possible films and reactants, we will choose instead to focus on silicon dioxide, silicon nitride, polysilicon, and epitaxial silicon as the films of interest. At the same time, we will only look at those reactant gases that have been used for integrated circuit manufacture. An excellent survey of the film types that can be deposited by CVD and the many reactants that have been used to obtain them has been given by Kern.1... 

Multi-wall carbon nanotube (CNT) arrays synthesis by the atmospheric pressure CVD method has been investigated. Thermal decomposition of fluid hydrocarbons (o- and p-xylole f sl liC l which as a solution with the volatile catalyst (ferrocene Fe(CsHs)2) was introduced into the synthesis zone by injection was employed. Different metal/dielectric/semiconductor (MDS) structures, in particular Ti/SifT/Si. AI2O3 membrane/Ni catalyst were used. CNTs growth selectivity can be regulated under certain conditions. The vertically aligned close-packed CNT arrays have been obtained as well as single CNTs in the pores of AI2O3 matrix with Ni catalyst. 

Dielectric Deposition Systems. The most common techniques used for dielectric deposition include chemical vapor deposition (CVD), sputtering, and spin-on films. In a CVD system thermal or plasma energy is used to decompose source molecules on the semiconductor surface (189). In plasma-enhanced CVD (PECVD), typical source gases include silane, SiH, and nitrous oxide, N2O, for deposition of siUcon nitride. The most common CVD films used are siUcon dioxide, siUcon nitride, and siUcon oxynitrides. 

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