Mechanisms of homo- and heteroepitaxial growth of SiC on α-SiC(0001) by solid-source molecular beam epitaxy

Fissel, A.; Pfennighaus, K.; Kaiser, Ute; Schröter, Bernd; Richter, Wolfgang

doi:10.1007/s11664-999-0015-0

Cited by 12 publications

(6 citation statements)

References 46 publications

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“…Many twins T and stacking faults SF are visible in the image. This surface is the substrate for the next epitaxial layer [86]. For homo-epitaxy the same polytype crystal continues to grow and for hetero-epitaxy a new polytype will nucleate.…”

Section: Ipycmentioning

confidence: 99%

Diffusion of fission products and radiation damage in SiC

Malherbe

2013

J. Phys. D: Appl. Phys.

103

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A major problem with most of the present nuclear reactors is their safety in terms of the release of radioactivity into the environment during accidents. In some of the future nuclear reactor designs, i.e. Generation IV reactors, the fuel is in the form of coated spherical particles, i.e. TRISO (acronym for Triple Coated Isotropic) particles. The main function of these coating layers is to act as diffusion barriers for radioactive fission products, thereby keeping these fission products within the fuel particles, even under accident conditions. The most important coating layer is composed of polycrystalline 3C-SiC. This paper reviews the diffusion of the important fission products (silver, caesium, iodine and strontium) in SiC. Because radiation damage can induce and enhance diffusion, the paper also briefly reviews damage created by energetic neutrons and ions at elevated temperatures, i.e. the temperatures at which the modern reactors will operate, and the annealing of the damage. The interaction between SiC and some fission products (such as Pd and I) is also briefly discussed. As shown, one of the key advantages of SiC is its radiation hardness at elevated temperatures, i.e. SiC is not amorphized by neutron or bombardment at substrate temperatures above 350°C. Based on the diffusion coefficients of the fission products considered, the review shows that at the normal operating temperatures of these new reactors (i.e. less than 950°C) the SiC coating layer is a good diffusion barrier for these fission products. However, at higher temperatures the design of the coated particles needs to be adapted, possibly by adding a thin layer of ZrC.

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Section: Ipycmentioning

confidence: 99%

Diffusion of fission products and radiation damage in SiC

Malherbe

2013

J. Phys. D: Appl. Phys.

103

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“…The most serious problem in the growth of SiC heterostructures is the occurrence of incoherent twin ͑double-position͒ boundaries ͑DPB͒ when 3C-SiC is involved. Recently, we have already 6,8,9 shown that the growth of 3C-SiC can be significantly improved by an alternating supply of Si and C at medium T ͑1430 K͒ on on-axis ␣-SiC͑0001͒. diameter of DPB domains was found to be increased to some hundreds m. That already demonstrated the importance of adatom mobility and nucleation conditions for the growth of single domain 3C-SiC layers.…”

mentioning

confidence: 92%

“…Afterwards a SiC-buffer layer was grown via step flow at the same T and a carbon flux of 10 13 cm Ϫ2 s Ϫ1 , cor-responding to Rϭ7.5 nm/h, a rate low enough to prevent nucleation also on nominal on-axis substrates. 6,8 The final step morphology mostly consists of steps one unit cell in height.…”

mentioning

confidence: 99%

Advances in the molecular-beam epitaxial growth of artificially layered heteropolytypic structures of SiC

Fissel

Schröter

Kaiser

et al. 2000

Applied Physics Letters

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The controlled growth of SiC heteropolytypic structures consisting of hexagonal and cubic polytypes has been performed by solid-source molecular-beam epitaxy. On on-axis substrates, 4H/3C/4H–SiC(0001) and 6H/3C/6H–SiC(0001) structures were obtained by first growing the 3C–SiC layer some nanometer thick at lower substrate temperatures (T=1550 K) and Si-rich conditions and a subsequent growth of α-SiC on top of the 3C–SiC layer at higher T (1600 K) under more C-rich conditions. On off-axis substrates, multiheterostructures consisting of 4H/3C- or 6H/3C-stacking sequences were also obtained by first nucleating selectively one-dimensional wire-like 3C–SiC on the terraces of well-prepared off-axis α-SiC(0001) substrates at low T(<1500 K). Next, SiC was grown further in a step-flow growth mode at higher T and Si-rich conditions. After the growth, many wire-like regions consisting of 3C–SiC were found also within the hexagonal layer material matrix indicating a simultaneous step-flow growth of both the cubic and the hexagonal SiC material.

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“…growth rate or purity. The temperature limitation has a direct impact on SiC polytype which can be grown by MBE so that 3C-SiC is most commonly obtained using this technique [58,59]. And this is what is happening when adding Ge to SiC growth by MBE [39,60].…”

Section: Increasing Ge Incorporationmentioning

confidence: 99%

Growth and doping of silicon carbide with germanium: a review

Ferro

2021

Critical Reviews in Solid State and Materials Sciences

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This paper review the research works made so far in associating Ge isoelectronic element to SiC crystals, either by incorporating it inside SiC matrix or for assisting SiC epitaxial growth. The incorporation mechanism and level of incorporation of Ge in SiC during crystal growth with different techniques (sublimation, chemical vapor deposition, vapor-liquid-solid) are compared and discussed. Ge doping level as high as 2-3x10 20 at.cm -3 can be reached without affecting SiC crystalline quality but generating some strain. Higher Ge incorporation levels up to few at% can be reached using farer-toequilibrium conditions such as ion implantation or molecular beam epitaxy. The former allows retaining 4H-SiC polytype while the latter leads exclusively to defective 3C-SiC polytype. Adding Ge to SiC crystal growth was also used for promoting 3C-SiC heteroepitaxy on Si and on -SiC substrates, the latter case being more successful. The reported modifications and improvements of SiC crystalline and electronic properties by the incorporation of Ge element are discussed in order to draw or clearer picture of SiC:Ge material. Based on such discussion, some short-and long-term perspectives are proposed 1-IntroductionThe development of any semiconductor based technology requires mastering and understanding a high number of fabrication steps which can be very complex. On material aspect, crystalline quality and purity are essential. The former allows reaching the predicted properties of the material while the latter allows working on the intentional doping type and level of the semiconductor. The n and p type doping elements are usually well identified for each semiconductor and their incorporations using different elaboration techniques are widely documented. The incorporation of metallic impurities is also commonly investigated for improving the semiconductor properties such as increasing resistivity (Fe in GaN [1], V in 4H-SiC [2]), tuning optical emission (Er in GaN [3] or Si [4]) or providing magnetic properties (Mn in GaAs [5] or Ge [6]). Isoelectronic (also named isovalent) doping is similarly frequent in the case of binary (III-V or II-VI) semiconductor compounds due to the usual important miscibility between elements of the same column and/or valence. It can lead to bandgap tuning [7,8], obtaining of new properties [9,10] or crystalline improvement [11,12].In the particular cases of column IVB semiconductors, the isoelectronic doping concerns only elements of the same column which reduces substantially the possibilities. Important solubility exists

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Mechanisms of homo- and heteroepitaxial growth of SiC on α-SiC(0001) by solid-source molecular beam epitaxy

Cited by 12 publications

References 46 publications

Diffusion of fission products and radiation damage in SiC

Diffusion of fission products and radiation damage in SiC

Advances in the molecular-beam epitaxial growth of artificially layered heteropolytypic structures of SiC

Growth and doping of silicon carbide with germanium: a review

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