Nitrogen Incorporation during Seeded Sublimation Growth of 4H-SiC and 6H-SiC

International audienceNitrogen Incorporation during Seeded Sublimation Growth of 4H-SiC and 6H-Si

Improvement of the Specific Contact Resistance on P-Type 4H-SiC by Using a Highly P-Typed Doped 4H-SiC Layer Selectively Grown by VLS Transport

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High temperature electrical transport study of Si-doped AlN

Electrical transport (resistivity and Hall Effect) have been studied in silicon doped aluminum nitride (AlN) thick epitaxial layers from 250 K up to 1000 K. The investigated samples, grown by molecular beam epitaxy were characterized by n-type conduction with an ambient temperature free carrier concentration of about ~ 1 x 10^15 cm^3. The donor level, situated about 250 meV below the conduction band edge, was found to be responsible for the experimentally observed increase of free carrier concentration withtemperature. The temperature dependence of carrier mobility has been analyzed in the framework of a multimode scattering model. In the investigated samples the main scattering mechanism is supposed to be dislocation scattering

LTPL investigation of N-Ga and N-Al donor-acceptor pair spectra in 3C-SiC layers grown by VLS on 6H-SiC substrates

Ga-doped 3C-SiC layers have been grown on on-axis 6H-SiC (0001) substrates by the VLS technique and investigated by low temperature photoluminescence (LTPL) measurements. On these Ga-doped samples, all experimental spectra collected at 5K were found dominated by strong N-Ga donor-acceptor pair (DAP) transitions and phonon replicas. As expected, the N-Ga DAP zero-phonon line (ZPL) was located at lower energy (similar to 86 meV) below the N-Al one. Fitting the transition energies for the N-Al close DAP lines gave 251 meV for the Al acceptor binding energy in 3C-SiC and, by comparison, 337 meV for the Ga acceptor one

Combined effects of Ga, N, and Al codoping in solution grown 3C-SiC

We report on Ga-doped 3C-SiC epitaxial layers grown on on-axis (0001) 6H-SiC substrates using the vapor-liquid-solid technique and different Si1-xGax melts. The resulting samples have been investigated using secondary ion mass spectroscopy (SIMS), micro-Raman spectroscopy (mu-R) and, finally, low temperature photoluminescence (LTPL) spectroscopy. From SIMS measurements we find Ga concentrations in the range of 10(18) cm(-3), systematically accompanied by high nitrogen content. In good agreement with these findings, the mu-R spectra show that the Ga-doped samples are n-type, with electron concentrations close to 2x10(18) cm(-3). As expected, the LTPL spectra are dominated by strong N-Ga donor-acceptor pair (DAP) transitions. In one sample, a weak additional N-Al DAP recombination spectrum is also observed, showing the possibility to have accidental codoping with Ga and Al simultaneously. This was confirmed on a non-intentionally doped 3C-SiC (witness) sample on which, apart of the usual N and Al bound exciton lines, a small feature resolved at 2.35 eV comings from neutral Ga bound excitons. Quantitative analyses of the DAP transition energies in the Ga-doped and witness sample gave 346 meV for the optical binding energy of Ga acceptors in 3C-SiC against 251 meV for the Al one. The conditions for the relative observation of Ga and Al related LTPL features are discussed and the demonstration of room temperature luminescence using Ga doping is done. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3455999