Chemical Vapor Deposition

Dr. Russell Binions shares some personal recollections and reflections on EuroCVD 18 held in Kinsale, just south of Cork, where everyone experienced Céad Mile Fáilte – a hundred thousand welcomes − of Irish hospitality.

ALD of TaN thin films is explored using the combination between the thermodynamical behavior of the precursor, mass transfer in the reactor and the operating conditions. TaN thin film has been deposited on very complex shape substrates, such as nanodots, TSV, and silicon.

The present review article describes recent advances in the studies of solid polymer fuel cell electrodes. It emphasizes on CVD, PECVD and (PE)MOCVD as well as plasma sputtering techniques for growing such electrodes. Interest of each method is analyzed in terms of fuel cell performances.

In order to better understand the mechanisms involved during silicon deposition from silane SiH₄ into agglomerates of submicronic particles treated by Fluidized Bed CVD, two models have been developed. In the first one, classical equations of diffusion/reaction in porous medium have been solved whereas in the second case, the multifluid eulerian code MFIX has been used by considering the entire surface of particles.

A numerical tool based on Monte Carlo Random Walks in 3D images is presented as a solution for direct simulation of chemical vapor infiltration and of chemical vapor deposition over a patterned substrate. The code can also be used for determination of effective transport and reaction properties in a porous medium. Validations and application cases are shown and discussed.

Thin films of organosilicon materials are grown on micropatterned silicon substrates from the decomposition of the tetramethylsiloxane precursor by plasma-enhanced (PECVD) and remote plasma-enhanced (RPECVD) chemical vapor deposition. Fourier Transform IR spectroscopy and Scanning Electron Microscopy of the samples was used for this comparative study. The effects of pattern size and shape defined by the aspect ratio parameter, on the local growth rate are studied more specifically for trenches for both PECVD and RPECVD processes.

The effect of pulsed-pressure MOCVD processing parameters on conformality was studied by TiO₂ deposition on micron-scale and nano-scale features on Si and Si₂N₃ wafer samples. A statistical measure for conformality is presented. The conformality is shown to be insensitive to processing parameters over a wide range of pulse exposure, pressure and precursor concentration for growth rates from 0.5 nm/pulse to 2.4 nm/pulse.

ZnO nanowires arrays parallel to the substrate were directly deposited by magnetron sputtering selectively on the top of nanometric silicon line patterns prepared as a template. This method of synthesis is very simple and avoids the complicated steps of ZnO lithography. The nano-line template patterns were created by laser interference lithography combined with deep reactive ion etching. The nanowires exhibited a typical photoluminescence spectrum of ZnO.

This short review aims at giving readers information about Supercritical Fluid Chemical Deposition process (SFCD) for metal deposition as an alternative and complementary process to CVD. In particular, we highlight different examples of inorganic deposition (films or nanostructures) on various substrates among which are carbon nanotubes (CNTs) or silicon nanopatterned substrates.

We develop a model describing ballistic transport of precursors in an atomic layer deposition process for conformal deposition in high-aspect-ratio pore structures. Precursor transmission probability functions describing fluxes between pore surface features are developed, coupled to ALD surface reaction models, spatially discretized, and integrated over each precursor exposure period. Predictions from our dynamic model are compared to four previously published studies of ALD in nanopores to validate our simulator.

Physical vapor deposition (PVD) and chemical vapor deposition (CVD) are promising techniques for the deposition of thin films. In order to compare their ability to coat complex shaped surfaces, a micro-patterned silicon wafer has been developed. Aluminum thin films were deposited on this model substrate by pulsed laser deposition (PLD), magnetron sputtering (MS); and metal organic chemical vapor deposition (MOCVD). Results show that deposition by MOCVD in optimized conditions yield to conformal deposits. With MS, side and bottom thicknesses can be tailored by playing with the pattern dimensions, while PLD allows coating of a substrate, with the original pattern shape being transferred into the growing film.