Epitaxial growth of 3C-SiC onto silicon substrate by VLS transport using CVD-grown 3C-SiC seeding layer

International audienc

Realization and characterization of carbonic layers on 4H-SiC for electrochemical detections

International audienceFor electrochemical use, carbon materials exhibit better behaviors than metallic gold or platinum electrodes, in terms of detection limit, potential range and sensibility [1]. For these reasons, research has focused its interest in these materials. One advantage of these materials is that they can be prepared at the surface of different substrates. In this work, we aim at preparing diamond, graphene and pyrolyzed photoresist films at the surface of silicon carbide (4H-SiC), which is considered to be a biocompatible material. These layers are to be more attractive than glassy carbon, one of the cheapest and broadly used carbon material in electrochemistry. Our layers present the advantage to be able to be patterned, to resist high temperature treatments and also give the possibility to include all them in SiC technological steps for the preparation of more elaborate structures

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

Graphene on 4H-SiC for terahertz transistors and ferroelectric non-volatile memories

21 - 25 September, 2014International audienceno abstrac

Realization of a single layer graphene field effect transistor

May 11-15, 2015.International audienceGraphene is a semiconductor with zero band gap, linear energy dispersion, and linear density of electronic states. One of its most important properties is a strong electric field effect which leads to an electrostatically tunable carrier density in the range of n < 1e14 cm-2. Together with high carrier mobilities for both electrons and holes (as high as 10000 cm2/V.s at room temperature), this attracts a lot of attention to graphene as a possible material for a future high-speed field effect transistor (FET). Graphene layer was synthetized from silicon carbide wafers (SiC) by evaporating Si atoms from 4HSiC surface at high temperature thanks to a high energy electron beam in UHV. The formation of single layer graphene has been confirmed by Raman spectroscopy: peaks at 1580 cm-1 (G-peak) and 2690 cm-1 (2D peak), originated from graphene in-plane vibrational modes. After deposition of SiO2 functional oxide, the whole layers were patterned to realize a FET device. The graphene channel has width about 40μm and length between 2μm and 16μm. The application of voltage up to 9V at room temperature on the binary oxide gate leads to on-off working operation with a variation about 600% of the drain current

Graphene on 4H-SiC for terahertz transistors and ferroelectric non-volatile memories

21 - 25 September, 2014International audienceno abstrac

Nondestructive Evaluation of Photo-Electrical Properties of 3C-SiC (111) Homoepitaxial Layers Grown by CVD

International audienceFree carrier absorption (FCA) and picosecond light-induced transient grating (LITG) techniques were applied to study the photoelectrical properties of 3C-SiC(111) homoepitaxial layers grown by CVD method on VLS (vapour-liquid-solid) grown seeds. The thickness of the CVD layers was ~10.5 µm with non-intentional type doping of n (~ 1017 cm-3) or p (<1015 cm-3). The carrier lifetime and the diffusion coefficient were measured as the function of the sample temperature, the injected excess carrier density at different growth parameters. At room temperature the ambipolar diffusion coefficient was Da=2.5-3 cm2/s, while the lifetime was in the range of 12-18 ns. The best structural and electrical properties were obtained for a CVD layer grown at high, 1600 °C temperature

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

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