From ec5db38b81f004086fed58e56b828200ba59c1f6 Mon Sep 17 00:00:00 2001 From: hackbard Date: Wed, 2 Feb 2011 17:44:02 +0100 Subject: [PATCH] mbe started --- bibdb/bibdb.bib | 37 +++++++++++++++++++++++++++++++++++++ posic/thesis/sic.tex | 20 +++++++++++++++++--- 2 files changed, 54 insertions(+), 3 deletions(-) diff --git a/bibdb/bibdb.bib b/bibdb/bibdb.bib index 761a8d3..25d9dcd 100644 --- a/bibdb/bibdb.bib +++ b/bibdb/bibdb.bib @@ -1930,6 +1930,43 @@ notes = "mbe 3c-sic on si and 6h-sic", } +@Article{fissel96, + author = "Andreas Fissel and Ute Kaiser and Kay Pfennighaus and + Bernd Schr{\"{o}}ter and Wolfgang Richter", + collaboration = "", + title = "Growth of 6{H}--Si{C} on 6{H}--Si{C}(0001) by + migration enhanced epitaxy controlled to an atomic + level using surface superstructures", + publisher = "AIP", + year = "1996", + journal = "Applied Physics Letters", + volume = "68", + number = "9", + pages = "1204--1206", + keywords = "MICROSTRUCTURE; MOLECULAR BEAM EPITAXY; MORPHOLOGY; + NUCLEATION; SILICON CARBIDES; SURFACE RECONSTRUCTION; + SURFACE STRUCTURE", + URL = "http://link.aip.org/link/?APL/68/1204/1", + doi = "10.1063/1.115969", + notes = "ss mbe sic, superstructure, reconstruction", +} + +@Article{righi03, + title = "Ab initio Simulations of Homoepitaxial Si{C} Growth", + author = "M. C. Righi and C. A. Pignedoli and R. Di Felice and + C. M. Bertoni and A. Catellani", + journal = "Phys. Rev. Lett.", + volume = "91", + number = "13", + pages = "136101", + numpages = "4", + year = "2003", + month = sep, + doi = "10.1103/PhysRevLett.91.136101", + publisher = "American Physical Society", + notes = "dft calculations mbe sic growth", +} + @Article{borders71, author = "J. A. Borders and S. T. Picraux and W. Beezhold", collaboration = "", diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex index 252a29b..fc0998a 100644 --- a/posic/thesis/sic.tex +++ b/posic/thesis/sic.tex @@ -177,17 +177,31 @@ However, mismatches in the thermal expansion coefficient and the lattice paramet The alternative attempt to grow SiC on SiC substrates has shown to drastically reduce the concentration of defects in deposited layers. By CVD, both, the 3C \cite{kong88,powell90} as well as the 6H \cite{kong88_2,powell90_2} polytype could be successfully grown. -In order to obtain the homoepitactically grown 6H polytype, off-axis 6H-SiC wafers are required as a substrate \cite{kimoto93}. +In order to obtain the homoepitaxially grown 6H polytype, off-axis 6H-SiC wafers are required as a substrate \cite{kimoto93}. %In the so called step-controlled epitaxy, lateral growth proceeds from atomic steps without the necessity of preceding nucleation events. Investigations indicate that in the so-called step-controlled epitaxy, crystal growth proceeds through the adsorbtion of Si species at atomic steps and their carbonization by hydrocarbon molecules. This growth mechanism does not require two-dimensional nucleation. Instead, crystal growth is governed by mass transport, i.e. the diffusion of reactants in a stagnant layer. In contrast, layers of the 3C polytype are formed on exactly oriented \hkl(0 0 0 1) 6H-SiC substrates by two-dimensional nucleation on terraces. +{\color{red} Source of APB defects ...} However, lateral 3C-SiC growth was also observed on low tilt angle off-axis substrates originating from intentionally induced dislocations \cite{powell91}. Additionally, 6H-SiC was observed on clean substrates even for a tilt angle as low as \unit[0.1]{$^{\circ}$} due to low surface mobilities that facilitate arriving molecules to reach surface steps. Thus, 3C nucleation is assumed as a result of migrating Si and C cointaining molecules interacting with surface disturbances by a yet unknown mechanism, in contrast to a model \cite{ueda90}, in which the competing 6H versus 3C growth depends on the density of surface steps. - -MBE ... advantages ... and so on ... +{\color{red} This can be employed to create 3C layers with reduced density of APB defects.} + +Lower growth temperatures, a clean growth ambient, in situ control of the growth process, layer-by-layer deposition and the possibility to achieve dopant profiles within atomic dimensions due to the reduced diffusion at low growth temperatures reveal MBE as a promising technique to produce SiC epitaxial layers. +gas source ... 3C on 6H +3C on 3C homoepitaxy by ALE +6H on 6H ... +Problem of gas source ... strong adsorption and incorporation of atomic decomposited hydrogen of the gas phase reactants at low temperatures. +Growth rate lower than desorption rate of hydrogen ... +Solid source MBE may be the key to avoid such problems ... +Realized on and off-axis 3C on 4H and ... \cite{fissel95,fissel95_apl} ... +Nonstoichiometric reconstruction plays a relevenat role ... handled by Si/C flux ratio ... \cite{fissel96,righi03} ... +change in adlayer thickness and, consequently, in the surface super structure leading to growth of another polytype \cite{fissel95} ... +Possibility to grow heterostructures (band gap engineering) by careful control of the Si/C ratio and Si excess. + +To summarize ... remaining obstacles are ... APB in 3C ... and micropipes in hexagonal SiC? \section{Ion beam synthesis of cubic silicon carbide} -- 2.39.2