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 I-passivated Si surfaces were studied. X-ray photoelectron spectroscopy showed that the passivated Si surfaces were free of silicon oxides and carbides. Remarkable enhancement in nucleation was achieved on passivated surfaces and the nucleation density obtained on a Br-passivated Si surface reached ${10}^{10}{\mathrm{cm}}^{\mathrm{-}2}.$ Programmable temperature desorption revealed that the adsorbate desorption 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 emission current from the passivated surfaces, which was related to the degree of nucleation. Nucleation enhancement was shown to be greater when the adsorbate 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 an effective approach for diamond heteroepitaxial nucleation.

• Received 15 December 1999

DOI:https://doi.org/10.1103/PhysRevB.62.17134