Spin-seeding approach for diamond growth on large area silicon-wafer substrates

The growth of polycrystalline diamond by chemical vapor deposition requires a substrate pre-treatment in order to achieve thin, high-quality, and pore-free diamond layers. Seeding the substrate by immersing it into a nanodiamond (ND) dispersion is most commonly used today, since it yields a high-density seed layer (>1011?cm-2) and leads to a thin closed polycrystalline diamond film. Nevertheless, in a nanoelectronics fabrication facility it would be advantageous to use spinning for seeding the substrate as it is already well established for resist coating and spray etching. Additionally, each wafer would use a fresh and limited amount of seeding dispersion which will not be contaminated due to a certain number of immersion-seeding runs. Therefore, we carried out a detailed study of the spin-seeding technique in terms of seed density and its impact on diamond layer quality. Our work shows that by the spin-seeding approach, homogeneous seed layers with a seeding density up to 5 x 1010?cm-2 can be obtained on both 100 and 200?mm silicon wafers using 5 and 20?mL of a colloidal dispersion, respectively. ND dispersed in water +10% (v/v) ethanol gave the best results in terms of seeding density and wetting of the substrate surface.