Surface passivation in diamond nucleation

Surface passivation is introduced to suppress the deleterious effect of Si surface oxides and thus enhance diamond heteroepitaxial nucleation. Surface composition and diamond nucleation and growth on H-, Br-, and 1-passivated Si surfaces were studied. X-ray photoelectron spectroscopy showed that the passivated Si surfaces were free of silicon oxides and carbides. Remarkabl e enhancement in nucleation was achieved on passivated surfaces and the nuc leation density obtained on a Br-passivated Si surface reached 10(10) cm(-2 ), Programmable temperature desorption revealed that the adsorbate desorpti on temperature increased in the order of H, I, and Br passivation. The same order of increase was also observed in the saturation value of electron em ission current from the passivated surfaces, which was related to the degre e of nucleation. Nucleation enhancement was shown to be greater when the ad sorbate desorption temperature is closer to the nucleation temperature, so that more adsorbate- and oxide-free Si surface area would be available for nucleation. The study established that surface passivation is potentially a n effective approach for diamond heteroepitaxial nucleation.