DIAMOND NUCLEATION AND GROWTH AT THE EARLY STAGES ON SI(100) MONITORED BY ELECTRON SPECTROSCOPIES

Diamond growth on Si(100) is studied by scanning Auger microscopy (SAM ), Auger electron spectroscopy (AES), electron loss spectroscopy (ELS) and X-ray photoelectron spectroscopy (XPS) focussing on the early sta ges of nucleation and growth. The low nucleation density allows us to monitor the evolution of both the substrate and the deposit intensitie s during the deposition process. Using the structural and chemical ima ging probe provided by scanning Auger electron microscopy, we localize areas formed by carbon, only of diamond-type, and featureless areas w ith C, Si and O. The carbon nature on these last domains is initially a complex mixture of amorphous carbon, carbide and diamond. The amorph ous deposit rapidly disappears (30 min), but the occurrence of surface carbide is still detected even after 120 min of growth. The surface c arbon content, recorded both by AES focussed on the featureless domain s and by XPS, initially drops. This is interpreted by the formation of silicon carbide embedding or removing the amorphous carbon layer. We identify three different sites of nucleation, which are (i) diamond se eds left by the substrate pretreatment; (ii) amorphous carbon at the v ery beginning of the nucleation process and (iii) silicon carbide. The n the diamond growth and the carbide formation are competitive process es, limited by (i) the reactive content in the gas phase and (ii) diff usion and etching of the silicon.