Early Stages of Polycrystalline Diamond Film Deposition on Seeded Substrates

This chapter is dedicated to several developments in early-stage polycrystalline diamondPolycrystalline diamond (PCDPCD) film deposition on substrates seeded with diamond particles, focusing on films thinner than 500 nm — namely nanocrystalline diamondNanocrystalline diamond films. After providing an overview of the field, we delineate a strategy for detecting incubationIncubation during the plasma-enhanced chemical vaporPlasma-enhanced chemical vapor deposition of PCDPCD films. That strategy is based on in-situ measurements in which a laser beam reflects from a substrate and reaches a light detector, granted that the PCDPCD film is continuous after a specific deposition time. We find from a series of systematic experiments that, besides plasma composition, incubationIncubation can depend on temperature and particle size, which aligns with classical nucleation theoryNucleation theory. A simple model for predicting the light detector signal at the early deposition stages, when most diamond particles are isolated, is also discussed. In the last section, we provide an overview of recent advances in simulating the deposition of polycrystalline films on seeded substrates with an emphasis on closed and porous film morphology and pinhole survival.