A novel nucleation process (NNP), called the Rotter nucleation process in a recent review article, is described in detail in this paper. The NNP is based on the initial formation of a carbon film that, together with the diamond seeds on the surface (by standard seeding), plays an important role in the growth of the diamond layer. In the early stage, NNP induces a lateral growth mode that prevails until the initial grains coalesce and columnar growth begins. This method opens up new ways of using thin diamond films as encapsulation layers, and enables the formation of composite materials based on diamond.

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Abstract. A method for enhanced nucleation of diamond growth on non-diamond substrates is introduced via the results obtained in a wide variety of applications. The exact details of the method are still proprietary, but the outcome, as demonstrated in this paper, is unique and promises to be of great practical use. The main feature of the growth following the nucleation step is a very high density of nucleation sites which instantly started to grow over any structured surface in a perfectly conformal fashion.

CVD growth of uniform conformal polycrystalline diamond (PCD) coatings over complex three dimensional structures is very important material processing technique. It has been found that the nucleation and subsequent growth period is very critical for successful development of CVD diamond based technologies. There are many methods of enhancing diamond nucleation on foreign substrates-ultrasonic treatment with diamond seed suspension being the best among them. A combination of ultrasonic seeding (US) technique with prior treatment (PT) of the substrate under CVD diamond growth conditions for brief period of time, has found to be very effective in enhancing the diamond nucleation during CVD growth-together they are known as NNP. But successive usage of the same seeding suspension up to ten cycles deteriorates the seeding efficiency. 6 th seeding cycle onwards the silicon substrates are barely get covered by diamond crystallites. Five different diamond micron grits were used for seeding the silicon substrates and it is observed that US with the sub-micron particles (0.25 µm) is very effective in efficient nucleation of PCD on Si substrates. PT of the substrate somewhat negates the effect of successive use of the same seeding slurry but it is best to avoid recycling of the same seeding suspension using micron size diamond grits.

Surface acoustic wave (SAW) devices are key components in modern wireless communication systems. Besides being used as reflective delay lines, filters or resonators, SAW devices can be used as sensors and fixed‐code identification tags. Due to their high‐acoustic velo‐city, diamond films can be combined with piezoelectric materials to fabricate diamond‐based SAW devices with potential for high frequency applications. This paper presents results of coating commercial SAW delay lines with diamond films. The films were deposited on lithium niobate under different conditions in a hot filament chemical vapour deposition system. Seeding was performed using 6‐12 μm diamond grit and 20‐30 nm nano‐diamond particles based suspensions. After tuning the deposition conditions, dies of 74 MHz delay lines were coated with diamond. The quality, morphology and conformability of the coatings were evaluated by scanning electron microscopy (SEM) and Raman spectroscopy. The integrity of the interdigitated transducers (IDTs) after deposition was evaluated by SEM. S‐parameters of as‐bought and diamond‐coated dies were measured using a network analyser. Although the frequency response is attenuated after diamond deposition, integrity of the IDTs and the operating principle of the devices are kept intact. These preliminary results open the door to a simplified fabrication procedure of diamond‐based SAW devices. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The ultrasonic seeding of a substrate with diamond suspensions enriches the surface with nanometre-sized seeds that coalesce and form a closed conformal film during early stages of diamond growth. To get insight on seeds early growth and evaluate the seeding efficiency of different suspensions, silicon samples were exposed to diamond growth conditions before seeding; this leaves a thin carbon film on the substrate surface. Following this step samples were seeded with commercial nanodiamond suspensions, exposed again to growth conditions and characterised by SEM. Results showed that seeding suspensions played a role depending on particle size and nature of dispersing medium. Seeding density was larger and more uniform in samples pre-exposed to diamond growth conditions. The carbon film deposited during the pre-treatment improves deagglomeration of nanodiamond seeds via a more effective interaction between substrate surface and seeds. This procedure represents a viable way to grow thin conformal diamond coatings by HFCVD