Nitrogen Doping of 3C-SiC Single Crystals Grown by CF-PVT

International audienceWe present a structural and optical investigation of nitrogen-doped single crystals of cubic silicon carbide prepared by the continuous feed - physical vapour transport method. Self-nucleated crystals were produced which exhibited well faceted square and triangular shapes. KOH etching was used to characterize the Structural defects. like stacking faults and dislocations. The effect of changing the nitrogen flow rate oil the different crystalline orientations was investigated by Raman spectroscopy and low temperature photoluminescence techniques

Effects of Growth Conditions on the Low Temperature Photoluminescence Spectra of (111) 3C-SiC Layers Grown by Chemical Vapor Deposition on 3C-SiC Seeds grown by the Vapor-Liquid-Solid Technique

We report the results of a low temperature photoluminescence investigation of 3C-SiC samples grown by chemical vapor deposition on vapor-liquid-solid seeds. The main parameters tested in this series of samples were i degrees) the effects of changing the C/Si ratio and ii degrees) the growth temperature on the final growth product. On the first series the C/Si ratio varied from 1 to 14 for a constant growth temperature of 1550 C. For the second series, the growth temperature varied from 1450 to1650 degrees C by steps of 50 degrees C with a constant C/Si ratio equal to 3. According to this work, the best results (minimum incorporation of impurities and best crystal quality) were obtained when using a C/Si ratio of 3 at 1650 degrees C

Splitting of close N-Al donor-acceptor-pair spectra in 3C-SiC

Discrete series of lines have been observed for many years in N-Al DAP (Donor Acceptor Pair) spectra in 3C-SiC. Unfortunately, up to now, there has been no quantitative analysis for the splitting of lines in a given shell. This is done in this work for N-Al DAP spectra in 3C-SiC. The samples were non-intentionally doped 3C-SiC layers grown by CVD on a VLS seeding layer grown on a 6H-SiC substrate. From low temperature photoluminescence measurements, strong N-Al DAP emission bands were observed and, on the high energy side of the zero-phonon line, we could resolve a series of discrete lines coming from close pairs. Comparing with literature data, we show that the splitting energy for a given shell is constant and, to explain this shell substructure, we consider the non equivalent sets of sites for a given shell. Results are discussed in terms of the ion-ion interaction containing third and forth multipole terms

Investigation of low doped n-type and p-type 3C-SiC layers grown on 6H-SiC substrates by sublimation epitaxy

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

Silicon carbide (SiC) has long...

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Seeding layer influence on the low temperature photoluminescence intensity of 3C-SiC grown on 6H-SiC by sublimation epitaxy

We report on n-type 3C-SiC samples grown by sublimation epitaxy. We focus on the low temperature photoluminescence intensity and show that the presence of a first conversion layer, grown at low temperature, is not only beneficial to improve the homogeneity of the polytype conversion but, also, to the LTPL signal intensity. From the use of a simple model, we show that this comes from a reduced density of non-radiative recombination centers

Effects of Growth Conditions on the Low Temperature Photoluminescence Spectra of (111) 3C-SiC Layers Grown by Chemical Vapor Deposition on 3C-SiC Seeds grown by the Vapor-Liquid-Solid Technique

We report the results of a low temperature photoluminescence investigation of 3C-SiC samples grown by chemical vapor deposition on vapor-liquid-solid seeds. The main parameters tested in this series of samples were i degrees) the effects of changing the C/Si ratio and ii degrees) the growth temperature on the final growth product. On the first series the C/Si ratio varied from 1 to 14 for a constant growth temperature of 1550 C. For the second series, the growth temperature varied from 1450 to1650 degrees C by steps of 50 degrees C with a constant C/Si ratio equal to 3. According to this work, the best results (minimum incorporation of impurities and best crystal quality) were obtained when using a C/Si ratio of 3 at 1650 degrees C

Heavily p-Type Doping of Bulk 6H-SiC and 3C-SiC Grown from Al-Si Melts

International audienceWe report in this work, the solution growth of heavily p-type doped 3C-SiC and 6H-SiC. Description of the 3C and 6H-SiC crystals in terms of defects and resistivity are presented and discussed with respect to growth conditions such as temperature, Al content in the melt and seed polarity. Crystals and thick layers are investigated by means of TEM, NDIC microscopy and Raman

Splitting of close N-Al donor-acceptor-pair spectra in 3C-SiC

Discrete series of lines have been observed for many years in N-Al DAP (Donor Acceptor Pair) spectra in 3C-SiC. Unfortunately, up to now, there has been no quantitative analysis for the splitting of lines in a given shell. This is done in this work for N-Al DAP spectra in 3C-SiC. The samples were non-intentionally doped 3C-SiC layers grown by CVD on a VLS seeding layer grown on a 6H-SiC substrate. From low temperature photoluminescence measurements, strong N-Al DAP emission bands were observed and, on the high energy side of the zero-phonon line, we could resolve a series of discrete lines coming from close pairs. Comparing with literature data, we show that the splitting energy for a given shell is constant and, to explain this shell substructure, we consider the non equivalent sets of sites for a given shell. Results are discussed in terms of the ion-ion interaction containing third and forth multipole terms

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