From 63f584cf2855650f0a8ff2bdebe4f33cb9099378 Mon Sep 17 00:00:00 2001 From: hackbard Date: Tue, 19 Apr 2011 17:11:34 +0200 Subject: [PATCH] more lindner stuff, finished soon, hopefully! --- bibdb/bibdb.bib | 52 ++++++++++++++++++++++++++++++++++++++++++++ posic/thesis/sic.tex | 24 +++++++++++++++----- 2 files changed, 71 insertions(+), 5 deletions(-) diff --git a/bibdb/bibdb.bib b/bibdb/bibdb.bib index b2b9c19..c55a0e1 100644 --- a/bibdb/bibdb.bib +++ b/bibdb/bibdb.bib @@ -1226,6 +1226,58 @@ notes = "first time ibs at moderate temperatures", } +@Article{lindner96, + title = "Formation of buried epitaxial silicon carbide layers + in silicon by ion beam synthesis", + journal = "Materials Chemistry and Physics", + volume = "46", + number = "2-3", + pages = "147--155", + year = "1996", + note = "", + ISSN = "0254-0584", + doi = "DOI: 10.1016/S0254-0584(97)80008-9", + URL = "http://www.sciencedirect.com/science/article/B6TX4-3VSGY9S-8/2/f001f23c0b3bc0fc3fc683616588fbc7", + author = "J. K. N. Lindner and K. Volz and U. Preckwinkel and B. + Götz and A. Frohnwieser and B. Rauschenbach and B. + Stritzker", + notes = "dose window", +} + +@Article{calcagno96, + title = "Carbon clustering in Si[sub 1-x]{C}[sub x] formed by + ion implantation", + journal = "Nuclear Instruments and Methods in Physics Research + Section B: Beam Interactions with Materials and Atoms", + volume = "120", + number = "1-4", + pages = "121--124", + year = "1996", + note = "Proceedings of the E-MRS '96 Spring Meeting Symp. I on + New Trends in Ion Beam Processing of Materials", + ISSN = "0168-583X", + doi = "DOI: 10.1016/S0168-583X(96)00492-2", + URL = "http://www.sciencedirect.com/science/article/B6TJN-3VSHB0W-1S/2/164b9f4f972a02f44b341b0de28bba1d", + author = "L. Calcagno and G. Compagnini and G. Foti and M. G. + Grimaldi and P. Musumeci", + notes = "dose window, graphitic bonds", +} + +@Article{lindner98, + title = "Mechanisms of Si{C} Formation in the Ion Beam + Synthesis of 3{C}-Si{C} Layers in Silicon", + journal = "Materials Science Forum", + volume = "264-268", + pages = "215--218", + year = "1998", + note = "", + doi = "10.4028/www.scientific.net/MSF.264-268.215", + URL = "http://www.scientific.net/MSF.264-268.215", + author = "J. K. N. Lindner and W. Reiber and B. Stritzker", + notes = "intermediate temperature for sharp interface + good + crystallinity", +} + @Article{lindner99, title = "Controlling the density distribution of Si{C} nanocrystals for the ion beam synthesis of buried Si{C} diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex index 7228cbe..256e7db 100644 --- a/posic/thesis/sic.tex +++ b/posic/thesis/sic.tex @@ -243,13 +243,13 @@ The authors assumed that due to the auxiliary heating rather than ion beam heati Even better qualities by direct synthesis were obtained for implantations at \unit[950]{$^{\circ}$C} \cite{nejim95}. Since no amorphous or polycrystalline regions have been identified, twinning is considered to constitute the main limiting factor in the \ac{IBS} of SiC. -Further studies revealed the possibility to form buried layers of SiC by IBS at moderate substrate and anneal temperatures \cite{lindner95}. +Further studies revealed the possibility to form buried layers of SiC by IBS at moderate substrate and anneal temperatures \cite{lindner95,lindner96}. Different doses of C ions with an energy of \unit[180]{keV} were implanted at \unit[330-440]{$^{\circ}$C} and annealed at \unit[1200]{$^{\circ}$C} or \unit[1250]{$^{\circ}$C} for \unit[5-10]{h}. For a critical dose, which was found to depend on the Si substrate orientation, the formation of a stoichiometric buried layer of SiC exhibiting a well-defined interface to the Si host matrix was observed. In case of overstoichiometric C concentrations the excess C is not redistributed. -These investigations demonstrate the presence of an upper dose limit, which corresponds to a \unit[50]{at.\%} C concentration at the implantation peak, for the thermally induced redistribution of the C atoms from a Gaussian to a box-shaped depth profile upon annealing. -For higher concentrations the formation of strong C-C bonds is expected. -Increased temperatures are necessary for the dissociation of these C clusters. +These investigations demonstrate the presence of an upper dose limit, which corresponds to a \unit[53]{at.\%} C concentration at the implantation peak, for the thermally induced redistribution of the C atoms from a Gaussian to a box-shaped depth profile upon annealing. +This is explained by the formation of strong graphitic C-C bonds for higher C concentrations \cite{calcagno96}. +Increased temperatures exceeding the Si melting point are expected to be necessary for the dissociation of these C clusters. Furthermore, higher implantation energies were found to result in layers of variable composition exhibiting randomly distributed SiC precipitates. In another study \cite{serre95} high dose C implantations were performed at room temperature and \unit[500]{$^{\circ}$C} respectively. Implantations at room temperature lead to the formation of a buried amorphous carbide layer in addition to a thin C-rich film at the surface, which is attributed to the migration of C atoms towards the surface. @@ -257,7 +257,19 @@ In contrast, implantations at elevated temperatures result in the exclusive form Annealing at temperatures up to \unit[1150]{$^{\circ}$C} does not alter the C profile. Instead defect annihilation is observed and the C-rich surface layer of the room temperature implant turns into a layer consisting of SiC precipitates, which, however, are not aligned with the Si matrix indicating a mechanism different to the one of the direct formation for the high-temperature implantation. -.. lindner limit in dose -> 1250 +Based on these findings, a recipe was developed to form buried layers of single-crystalline SiC featuring an improved interface and crystallinity \cite{lindner99,lindner01,lindner02}. +Therefore, the dose must not exceed the stoichiometry dose, i.e. the dose corresponding to \unit[50]{at.\%} C concentration at the implantation peak. +Otherwise clusters of C are formed, which cannot be dissolved during post-implantation annealing at moderate temperatures below the Si melting point \cite{lindner96,calcagno96}. +Annealing should be performed for \unit[5-10]{h} at \unit[1250]{$^{\circ}$C} to enable the redistribution from the as-implanted Gaussian into a box-like C depth profile \cite{lindner95}. +The implantation temperature constitutes the most critical parameter, which is responsible for the structure after implantation and, thus, the starting point for subsequent annealing steps. + + +\cite{lindner98} sharp interface and good crystallinity + +improved two-temperature implantation \cite{lindner99}. + +By understanding these basic processes +... lindner limit in dose -> 1250 ... two temp implantation ... sharp interface By understanding some basic processes (32-36), \ac{IBS} nowadays has become a promising method to form thin SiC layers of high quality exclusively of the 3C polytype embedded in and epitactically aligned to the Si host featuring a sharp interface \cite{lindner99,lindner01,lindner02}. @@ -268,6 +280,8 @@ diffusion mechanism, lattice distortion, hmm ... extra section needed? \section{Assumed cubic silicon carbide conversion mechanisms} \label{section:assumed_prec} +... \cite{lindner99_2} ... + on surface ... md contraction along 110 ... kitabatake ... and ref in lindner ... rheed from si to sic ... in ibs ... lindner and skorupa ... -- 2.39.2