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Homoepitaxial growth of 4H-SiC could be achieved at 1500°C on off-oriented 4H-SiC{0001} substrates by means of a vapor phase epitaxial method. Grown layers showed specular smooth surfaces on both (0001)Si and (000)C faces. Doping of Ga during crystal growth was carried out and photoluminescence of grown layers was studied. Bluish-violet photoluminescence due to donor(N)-acceptor(Ga) pair recombination and recombination of a free electron with a hole at a Ga acceptor was observed. The emission attributed to the latter recombination process became dominant at high temperatures above 100 K. The luminescence of Ga-doped 4H-SiC was not quenched up to temperatures as high as 150 K, whereas the luminescence intensity of Al-doped 6H-SiC and 4H-SiC started to decrease at 70 and 85 K, respectively.

We have investigated the formation of nanocrystalline Si (nc-Si) in SiH4plasma using a pulsed-H2gas supply by very-high-frequency (VHF; 144 MHz) excitation. Nanocrystalline Si is formed in the gas phase of a SiH4plasma cell by the coalescence of radicals. The particle size of nc-Si is determined by the growth time of nc-Si in the plasma cell. Supplying H2into SiH4plasma enhances nucleation of nc-Si. When the H2gas supply is turned off, nucleated nc-Si particles grow larger in SiH4plasma. In the next cycle of H2gas supply, nc-Si particles grown in the previous cycle are pushed out of the cell into the deposition chamber. Using this method, fabrication of nc-Si with a diameter around 8 nm and a narrow spread (±1 nm) of particle size was realized.

This paper presents results on the fabrication of single electron tunneling devices using silicon nanocrystals. We prepare silicon nanocrystals of uniform particle size by very-high-frequency plasma processing and deposit them on a poly-silicon electrode structure having a very small inter-electrode separation of 26-70 nm. Current-voltage (I-V) characteristics show Coulomb blockade and Coulomb staircase at 77 K. For very narrow electrode separation, Coulomb staircase appears in I-Vcharacteristics even at room temperature.