Ref HAL: hal-00543642_v1
Exporter : BibTex | endNote
Résumé:

Both, n-type and p-type 3C-SiC samples grown on 6H-SiC substrates by sublimation epitaxy have been investigated. From low temperature photoluminescence studies, we demonstrate a low level of residual (n and/or p-type) doping with weak compensation, which is confirmed by secondary ion mass spectroscopy in the case of p-type samples.

Ref HAL: hal-00536664_v1
DOI: 10.1063/1.3455999
WoS: 000280000400016
Exporter : BibTex | endNote
8 Citations
Résumé:

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]

Ref HAL: hal-00390772_v1
Exporter : BibTex | endNote

Ref HAL: hal-00389410_v1
Exporter : BibTex | endNote
Résumé:

A detailed investigation of the Ge concentration in implanted samples has been carried out by SIMS and the effects affecting the depth distribution and measurement results have been determined. It is found that the MCs+ SIMS technique is best suited to investigate Gex(4H-SiC)1-x solid solutions up to x=0.2, while the O2 + SIMS configuration is limited to x=0.1. The Ge concentrations obtained by SIMS are very close to the nominal values. On the opposite, performing a comparison with previous RBS data, we find that the RBS values are systematically underestimated by ~30%. Finally, at very high dose, we find that some of the implanted species are lost by recoil and sputtering effects.

Ref HAL: hal-00389394_v1
Exporter : BibTex | endNote
Résumé:

Photoluminescence(PL)-topography is a powerful method to determine the charge carrier concentration of SiC-wafers. The following, work describes the development of a PL-topography method for the determination of charge carrier distribution in p-type SiC and shows the correlation of PL-Intensity and charge carrier concentration. With this setup it is possible to characterize wafers up to a size of 2" at room- and low temperature in a non-destructive way.

Ref HAL: hal-00389376_v1
Exporter : BibTex | endNote
Résumé:

We report on recent advances in liquid phase epitaxial (LPE) conversion of a bulk Si wafer into self standing 3C-SiC. This includes the role of the stress control within the (100) oriented "crucibles", the elaboration of crack-free (111) "crucibles" and the successful conversion of (100) and (111) oriented Si wafer. To date up to 100 mu m thick 3C-SiC(100) as well as 30 mu m thick crack-free 3C-SiC (111) materials have been obtained. The growth rate ranges from 20 to 100 mu m/h and locally can even reach similar to 1mm/h. In this work we focus on the structural, morphological and optical properties of the LPE-grown material.

Ref HAL: hal-00389278_v1
DOI: 10.1063/1.3098226, Article-Number = 063527
Exporter : BibTex | endNote
Résumé:

We report on a quantitative analysis of the effect of visible light laser irradiation (VLLI) on hexagonal (alpha) silicon carbide implanted with nitrogen and aluminum. In both cases of 4H and 6H polytypes we show that a short, but intense, irradiation with the 532 nm wavelength of a frequency-doubled neodymium: ytterbium aluminum garnet (Nd:YAG) laser results in a substantial reduction in the damage level produced by room temperature ion implantation. Up to now the recovery could not be made complete but, in the best conditions, it could reach similar to 80\% of the initial damage value. This is not enough to qualify VLLI as a full activation step but, rather, suggests to use it as a new processing tool in order to lower the constraints of high temperature ion implantation or, after implantation performed at room temperature, to reduce the total budget for high temperature annealing and activation steps.

Commentaires: Funding-Acknowledgement = CNM Barcelona (Spain) ; Franck Torregrossa from IBS-Rousset (France) Funding-Text = We greatly thank Philippe Godignon from CNM Barcelona (Spain) and Franck Torregrossa from IBS-Rousset (France) for providing us with the implanted samples investigated in this work. We also acknowledge Pierre Valvin and Philippe Arcade from GES for expert assistance with the irradiation and measurement procedures. Finally we acknowledge Marcin Zielinski and Servane Blanque from GES for performing SIMS and Raman measurements. One of us (D.J.B.) also acknowledges the CNRS and NRF for supporting grants during his stays in Montpellier