From 8254d4d5d47359044bea0b54ebd73f1fe5366d3e Mon Sep 17 00:00:00 2001 From: hackbard Date: Thu, 28 Apr 2011 17:18:02 +0200 Subject: [PATCH] finished substoichiometric c in si section, started conversion mechanism section --- bibdb/bibdb.bib | 190 ++++++++++++++++++++++++++++++++++++++++++- posic/thesis/sic.tex | 43 ++++++++-- 2 files changed, 225 insertions(+), 8 deletions(-) diff --git a/bibdb/bibdb.bib b/bibdb/bibdb.bib index ebcc267..076bf0e 100644 --- a/bibdb/bibdb.bib +++ b/bibdb/bibdb.bib @@ -935,6 +935,24 @@ author = "A. R. Bean and R. C. Newman", } +@Article{durand99, + author = "F. Durand and J. Duby", + affiliation = "EPM-Madylam, CNRS and INP Grenoble, France", + title = "Carbon solubility in solid and liquid silicon—{A} + review with reference to eutectic equilibrium", + journal = "Journal of Phase Equilibria", + publisher = "Springer New York", + ISSN = "1054-9714", + keyword = "Chemistry and Materials Science", + pages = "61--63", + volume = "20", + issue = "1", + URL = "http://dx.doi.org/10.1361/105497199770335956", + note = "10.1361/105497199770335956", + year = "1999", + notes = "better c solubility limit in silicon", +} + @Article{watkins76, title = "{EPR} Observation of the Isolated Interstitial Carbon Atom in Silicon", @@ -1142,6 +1160,26 @@ notes = "c diffusion due to si self-interstitials", } +@Article{fukami90, + author = "Akira Fukami and Ken-ichi Shoji and Takahiro Nagano + and Cary Y. Yang", + collaboration = "", + title = "Characterization of SiGe/Si heterostructures formed by + Ge[sup + ] and {C}[sup + ] implantation", + publisher = "AIP", + year = "1990", + journal = "Applied Physics Letters", + volume = "57", + number = "22", + pages = "2345--2347", + keywords = "HETEROJUNCTIONS; ION IMPLANTATION; HETEROSTRUCTURES; + FABRICATION; PN JUNCTIONS; LEAKAGE CURRENT; GERMANIUM + SILICIDES; SILICON; ELECTRICAL PROPERTIES; SOLIDPHASE + EPITAXY; CARBON IONS; GERMANIUM IONS", + URL = "http://link.aip.org/link/?APL/57/2345/1", + doi = "10.1063/1.103888", +} + @Article{strane93, author = "J. W. Strane and H. J. Stein and S. R. Lee and B. L. Doyle and S. T. Picraux and J. W. Mayer", @@ -2557,7 +2595,28 @@ quasi-direct one", } -@Conference{powell93, +@Article{eberl92, + author = "K. Eberl and S. S. Iyer and S. Zollner and J. C. Tsang + and F. K. LeGoues", + collaboration = "", + title = "Growth and strain compensation effects in the ternary + Si[sub 1 - x - y]Ge[sub x]{C}[sub y] alloy system", + publisher = "AIP", + year = "1992", + journal = "Applied Physics Letters", + volume = "60", + number = "24", + pages = "3033--3035", + keywords = "SILICON ALLOYS; GERMANIUM ALLOYS; CARBON ALLOYS; + TERNARY ALLOYS; SEMICONDUCTOR ALLOYS; MOLECULAR BEAM + EPITAXY; INTERNAL STRAINS; TEMPERATURE EFFECTS; CRYSTAL + STRUCTURE; LATTICE PARAMETERS; XRAY DIFFRACTION; PHASE + STUDIES", + URL = "http://link.aip.org/link/?APL/60/3033/1", + doi = "10.1063/1.106774", +} + +@Article{powell93, author = "A. R. Powell and K. Eberl and F. E. LeGoues and B. A. Ek and S. S. Iyer", collaboration = "", @@ -2579,6 +2638,93 @@ notes = "substitutional c in si by mbe", } +@Article{powell93_2, + title = "Si[sub 1-x-y]Ge[sub x]{C}[sub y] growth and properties + of the ternary system", + journal = "Journal of Crystal Growth", + volume = "127", + number = "1-4", + pages = "425--429", + year = "1993", + note = "", + ISSN = "0022-0248", + doi = "DOI: 10.1016/0022-0248(93)90653-E", + URL = "http://www.sciencedirect.com/science/article/B6TJ6-46J3RF2-8H/2/27fc231f28e4dc0a3b4770e5cf03257e", + author = "A. R. Powell and K. Eberl and B. A. Ek and S. S. + Iyer", +} + +@Article{osten94, + author = "H. J. Osten", + title = "Modification of Growth Modes in Lattice-Mismatched + Epitaxial Systems: Si/Ge", + journal = "physica status solidi (a)", + volume = "145", + number = "2", + publisher = "WILEY-VCH Verlag", + ISSN = "1521-396X", + URL = "http://dx.doi.org/10.1002/pssa.2211450203", + doi = "10.1002/pssa.2211450203", + pages = "235--245", + year = "1994", +} + +@Article{dietrich94, + title = "Lattice distortion in a strain-compensated + $Si_{1-x-y}$$Ge_{x}$${C}_{y}$ layer on silicon", + author = "B. Dietrich and H. J. Osten and H. R{\"u}cker and M. + Methfessel and P. Zaumseil", + journal = "Phys. Rev. B", + volume = "49", + number = "24", + pages = "17185--17190", + numpages = "5", + year = "1994", + month = jun, + doi = "10.1103/PhysRevB.49.17185", + publisher = "American Physical Society", +} + +@Article{osten94_2, + author = "H. J. Osten and E. Bugiel and P. Zaumseil", + collaboration = "", + title = "Growth of an inverse tetragonal distorted SiGe layer + on Si(001) by adding small amounts of carbon", + publisher = "AIP", + year = "1994", + journal = "Applied Physics Letters", + volume = "64", + number = "25", + pages = "3440--3442", + keywords = "SILICON ALLOYS; GERMANIUM ALLOYS; FILM GROWTH; CARBON + ALLOYS; TERNARY ALLOYS; MOLECULAR BEAM EPITAXY; TEM; + XRD; LATTICE PARAMETERS; EPITAXIAL LAYERS; TETRAGONAL + LATTICES", + URL = "http://link.aip.org/link/?APL/64/3440/1", + doi = "10.1063/1.111235", + notes = "inversely strained / distorted heterostructure", +} + +@Article{iyer92, + author = "S. S. Iyer and K. Eberl and M. S. Goorsky and F. K. + LeGoues and J. C. Tsang and F. Cardone", + collaboration = "", + title = "Synthesis of Si[sub 1 - y]{C}[sub y] alloys by + molecular beam epitaxy", + publisher = "AIP", + year = "1992", + journal = "Applied Physics Letters", + volume = "60", + number = "3", + pages = "356--358", + keywords = "SILICON ALLOYS; CARBON ALLOYS; BINARY ALLOYS; + SEMICONDUCTOR ALLOYS; SUPERLATTICES; MOLECULAR BEAM + EPITAXY; CHEMICAL COMPOSITION; TEMPERATURE EFFECTS; + FILM GROWTH; MICROSTRUCTURE", + URL = "http://link.aip.org/link/?APL/60/356/1", + doi = "10.1063/1.106655", +} + @Article{osten99, author = "H. J. Osten and J. Griesche and S. Scalese", collaboration = "", @@ -2682,6 +2828,48 @@ notes = "enhance of electron mobility in strained si", } +@Article{kissinger94, + author = "W. Kissinger and M. Weidner and H. J. Osten and M. + Eichler", + collaboration = "", + title = "Optical transitions in strained Si[sub 1 - y]{C}[sub + y] layers on Si(001)", + publisher = "AIP", + year = "1994", + journal = "Applied Physics Letters", + volume = "65", + number = "26", + pages = "3356--3358", + keywords = "SILICON CARBIDES; INTERNAL STRAINS; EPITAXIAL LAYERS; + CHEMICAL COMPOSITION; ELLIPSOMETRY; REFLECTION + SPECTROSCOPY; ELECTROOPTICAL EFFECTS; BAND STRUCTURE; + ENERGY LEVELS; ENERGYLEVEL TRANSITIONS", + URL = "http://link.aip.org/link/?APL/65/3356/1", + doi = "10.1063/1.112390", + notes = "strained si influence on optical properties", +} + +@Article{osten96, + author = "H. J. Osten and Myeongcheol Kim and K. Pressel and P. + Zaumseil", + collaboration = "", + title = "Substitutional versus interstitial carbon + incorporation during pseudomorphic growth of Si[sub 1 - + y]{C}[sub y] on Si(001)", + publisher = "AIP", + year = "1996", + journal = "Journal of Applied Physics", + volume = "80", + number = "12", + pages = "6711--6715", + keywords = "SILICON CARBIDES; CRYSTAL DEFECTS; FILM GROWTH; + MOLECULAR BEAM EPITAXY; INTERSTITIALS; SUBSTITUTION; + XRD; STRAINS", + URL = "http://link.aip.org/link/?JAP/80/6711/1", + doi = "10.1063/1.363797", + notes = "mbe substitutional vs interstitial c incorporation", +} + @Article{osten97, author = "H. J. Osten and P. Gaworzewski", collaboration = "", diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex index 5fe0564..c10fe17 100644 --- a/posic/thesis/sic.tex +++ b/posic/thesis/sic.tex @@ -330,24 +330,53 @@ Due to the absence of dislocations in the implanted region interstitial C is ass % link to strain engineering However, there is great interest to incorporate C onto substitutional lattice sites, which results in a contraction of the Si lattice due to the smaller covalent radius of C compared to Si \cite{baker68}, causing tensile strain, which is applied to the Si lattice. -Thus, substitutional C enables strain engineering of Si and Si/Si$_{1-x}$Ge$_x$ heterostructures \cite{yagi02,chang05,osten97}, which is used to increase charge carrier mobilities in Si as well as to adjust its band structure \cite{soref91,kasper91}. +Thus, substitutional C enables strain engineering of Si and Si/Si$_{1-x}$Ge$_x$ heterostructures \cite{yagi02,chang05,kissinger94,osten97}, which is used to increase charge carrier mobilities in Si as well as to adjust its band structure \cite{soref91,kasper91}. % increase of C at substitutional sites Epitaxial layers with \unit[1.4]{at.\%} of substitutional C have been successfully synthesized in preamorphized Si$_{0.86}$Ge$_{0.14}$ layers, which were grown by CVD on Si substrates, using multiple-energy C implantation followed by solid-physe epitaxial regrowth at \unit[700]{$^{\circ}$C} \cite{strane93}. The tensile strain induced by the C atoms is found to compensates the compressive strain present due to the Ge atoms. Studies on the thermal stability of Si$_{1-y}$C$_y$/Si heterostructures formed in the same way and equal C concentrations showed a loss of substitutional C accompanied by strain relaxation for temperatures ranging from \unit[810-925]{$^{\circ}$C} and the formation of spherical 3C-SiC precipitates with diameters of \unit[2-4]{nm}, which are incoherent but aligned to the Si host \cite{strane94}. During the initial stages of precipitation C-rich clusters are assumed, which maintain coherency with the Si matrix and the associated biaxial strain. -Using this technique a metastable solubility limit was achieved, which corresponds to a C concentration exceeding the solid solubility limit at the Si melting point by nearly three orders of magnitude and, furthermore, a reduction of the defect denisty near the metastable solubility limit is assumed if the regrowth temperature is increased by a rapid thermal annealing process \cite{strane96}. -By MBE ... \cite{powell93,osten99} +Using this technique a metastable solubility limit was achieved, which corresponds to a C concentration exceeding the solid solubility limit at the Si melting point by nearly three orders of magnitude and, furthermore, a reduction of the defect denisty near the metastable solubility limit is assumed if the regrowth temperature is increased by rapid thermal annealing \cite{strane96}. +Since high temperatures used in the solid-phase epitaxial regrowth method promotes SiC precipitation, other groups realized substitutional C incorporation for strained Si$_{1-y}$C$_y$/Si heterostructures \cite{iyer92,fischer95,powell93,osten96,osten99,laveant2002} or partially to fully strain-compensated (even inversely distorted \cite{osten94_2}) Si$_{1-x-y}$Ge$_x$C${_y}$ layers on Si \cite{eberl92,powell93_2,osten94,dietrich94} by \ac{MBE}. +Investigations reveal a strong dependence of the growth temperature on the amount of substitutionally incorporated C, which is increased for decreasing temperature accompanied by deterioration of the crystal quality \cite{osten96,osten99}. +While not being compatible to very-large-scale integration technology, C concentrations of \unit[2]{\%} and more have been realized \cite{laveant2002}. \section{Assumed silicon carbide conversion mechanisms} \label{section:assumed_prec} -Although much progress has been made in 3C-SiC thin film growth in the above-mentioned growth methods during the last decades, there is still potential -.. compatible to the established and highly developed technology based on silicon. +Although high-quality films of single-crystalline 3C-SiC can be produced by means of \ac{IBS} the precipitation mechanism in bulk Si is not yet fully understood. +Indeed, closely investigating the large amount of literature reveals controversial ideas of SiC formation assumed by the respective authors, which are reviewed in more detail in the following. -Although tremendous progress has been achieved in the above-mentioned growth methods during the last decades, available wafer dimensions and crystal qualities are not yet statisfactory. +\ac{HREM} studies \cite{werner96,werner97,eichhorn99,lindner99_2,koegler03} suggest the formation of C-Si dimers (dumbbells) on regular Si lattice sites, which agglomerate into large clusters indicated by dark contrasts and otherwise undisturbed Si lattice fringes in HREM, as can be seen in Fig.~\ref{fig:hrem:c-si}. + +A topotactic transformation into a 3C-SiC precipitate occurs once a critical radius of 2 nm to 4 nm is reached, which is manifested by the disappearance of the dark contrasts in favor of Moir\'e patterns (Fig.~\ref{fig:hrem:sic}) due to the lattice mismatch of \unit[20]{\%} of the 3C-SiC precipitate and c-Si. + +The insignificantly lower Si density of SiC ($\approx \unit[4]{\%}$) compared to c-Si results in the emission of only a few excess Si atoms. + +In contrast, investigations of strained Si$_{1-y}$C$_y$/Si heterostructures formed by MBE\cite{strane94,guedj98}, which incidentally involve the formation of SiC nanocrystallites, suggest an initial coherent precipitation by agglomeration of substitutional instead of interstitial C. + +Coherency is lost once the increasing strain energy of the stretched SiC structure surpasses the interfacial energy of the incoherent 3C-SiC precipitate and the Si substrate. + +These two different mechanisms of precipitation might be attributed to the respective method of fabrication. + +While in CVD and MBE surface effects need to be taken into account, SiC formation during IBS takes place in the bulk of the Si crystal. + +However, in another IBS study Nejim et~al.\cite{nejim95} propose a topotactic transformation that is likewise based on the formation of substitutional C. + +The formation of substitutional C, however, is accompanied by Si self-interstitial atoms that previously occupied the lattice sites and a concurrent reduction of volume due to the lower lattice constant of SiC compared to Si. + +Both processes are believed to compensate one another. + + +cites: + +ibs, c-si agglom: werner96,werner97,eichhorn99,lindner99_2,koegler03 +ibs, c sub: nejim95 +ibs, indicated c sub: martin90 + conclusions reeson8x, eichhorn02 +hetero, coherent sic by sub c: strane94,guedj98 + +more: taylor93, kitabatake contraction along 110, koegler03 -... \cite{lindner99_2} ... % -> skorupa 3.2: c sub vs sic prec -- 2.20.1