DEPOSITION OF DIAMOND ON PATTERNED SILICON SUBSTRATES

We have investigated the deposition of diamond on patterned (100) silicon substrates. Trenches rectangular in shape, up to 7 mu m in depth and with aspect ratios (i.e. depth-to-width ratios) up to 4 have been prepared by reactive plasma etching. Diamond deposition has been performed by micro wave-plasma-assisted chemical vapour de position preceded by an in situ bias pretreatment to support nucleation. Scanning electron microscopy studies show a strong dependence of nucleation on ion bombardment conditions. The nucleation density on vertical walls is three to five orders of magnitude less than at all locations in the direction of ion incidence. During diamond deposition following the bias pretreatment the growth of the layer is isotropic. The maximum film thickness which is available within the trenches amounts to half the trench width and does not depend on any other parameters.