Silicon-based epitaxy by chemical vapor deposition using novel precursor neopentasilane

Low temperature and high growth rates of epitaxial silicon deposition are desired for several practical reasons. The ability to grow epitaxial layers at low temperatures and for short times reduces the thermal budget and dopant diffusion. In has been previously shown that by increasing the silane order, (i.e. from silane to disilane to trisilane) the silicon growth rate increases for the same experimental conditions. The high-order silanes allow for the increase of growth rate but the cause has not been explained.;In this dissertation, we examine the use of neopentasilane (NPS) as the silicon source for silicon epitaxial growth by Chemical Vapor Deposition (CVD). The epitaxial layers grown with NPS are qualified using a variety of characterization techniques to determine the crystal quality, impurity levels in the films, and the electron and hole mobilities of the crystalline films. An atomistic mechanism for high-order silanes is proposed for the first time in this dissertation and tested rigorously against experimental results from our work and the data of other groups.;Both faster epitaxial growth rates and smoother silicon surfaces, implying a high surface diffusion coefficient, were achieved using the high-order silanes when compared with growth with silane. We hypothesize these effects are due more open sites on the surface during the growth. The increase is the result of surface-catalyzed reactions involving the consumption of surface hydrogen, thereby generating open sites. Indirect evidence of more open sites with high-order silanes was shown by measuring diborane and phosphorus adsorption.;The ability of high-order silanes to adsorb and deposit without the conventional hydrogen desorption to create open sites, and their ability to generate their own open surface sites are the main technological point of this dissertation. This unusual characteristic of high-order silanes makes NPS an attractive candidate for growth of heavily doped n-type silicon and Si:C epitaxial layers.