INFLUENCE OF THE NUCLEATION PROCESS ON THE PROPERTIES OF BORON DOPED DIAMOND FILMS DEPOSITED ON STRUCTURED SILICON

We report here on the preparation and characterization of polycrystalline boron doped diamond (BDD) thin films grown on structured silicon substrates using hot filament chemical vapor deposition (HFCVD) method. The BDD layers were grown in CH4 / H-2 gas mixture with trimethylboron (TMB) addition. Before diamond depositions, different nucleation processes were applied (diamond nanoparticles in deionized water or methanol, with/without oxygen plasma treatment). Layers with thicknesses from 0.2 to 1 mu m were deposited at varied ratios of B / C and CH4 / H-2 in the CH4 / H-2 / TMB gas mixture. Scanning electron microscopy (SEM) was used to analyze the samples. Oxygen plasma pretreatment was found as crucial for successful coating of the whole silicon pillars by diamond film including the bottom part. For some of the pretreatment methods (i.e. short nucleation time, < 5min), the HFCVD process resulted in formation of BDD caps on the top of silicon pillars.