X-Git-Url: https://hackdaworld.org/gitweb/?a=blobdiff_plain;f=posic%2Fthesis%2Fsic.tex;h=ee9f2c8731af991a789d7ee8009ad0d9ae864393;hb=9965e19a285d1af2b8b0a47d62f95904c6507a3f;hp=dd18103cda2349e07577e270ccfaf86423f0a892;hpb=609e8910dde4adea6d71f9083362ef0bc109d340;p=lectures%2Flatex.git diff --git a/posic/thesis/sic.tex b/posic/thesis/sic.tex index dd18103..ee9f2c8 100644 --- a/posic/thesis/sic.tex +++ b/posic/thesis/sic.tex @@ -168,12 +168,14 @@ During carbonization the Si surface is chemically converted into a SiC film with In a next step, the epitaxial deposition of SiC is realized by an additional supply of Si atoms at similar temperatures. Low defect densities in the buffer layer are a prerequisite for obtaining good quality SiC layers during growth, although defect densities decrease with increasing distance of the SiC/Si interface \cite{shibahara86}. Next to surface morphology defects such as pits and islands, the main defects in 3C-SiC heteroepitaxial layers are twins, stacking faults (SF) and antiphase boundaries (APB) \cite{shibahara86,pirouz87}. - - -off-axis \cite{shibahara86,powell87_2} ... -resulting in carb and growth \cite{kitabatake97} ... - -lower temps ... to limit thermal stress due to differing expansion coefficients ... +APB defects, which constitute the primary residual defects in thick layers, are formed near surface terraces that differ in a single-atom-height step resulting in domains of SiC separated by a boundary, which consists of either Si-Si or C-C bonds due to missing or disturbed sublattice information \cite{desjardins96,kitabatake97}. +However, the number of such defects can be reduced by off-axis growth on a Si \hkl(0 0 1) substrate miscut towards \hkl[1 1 0] by \unit[2]{$^{\circ}$}-\unit[4]{$^{\circ}$} \cite{shibahara86,powell87_2}. +This results in the thermodynamically favored growth of a single phase due to the uni-directional contraction of Si-C-Si bond chains perpendicular to the terrace steps edges during carbonization and the fast growth parallel to the terrace edges during growth under Si rich conditions \cite{kitabatake97}. +By MBE, lower process temperatures than these typically employed in CVD have been realized \cite{hatayama95,henke95,fuyuki97,takaoka98}, which is essential for limiting thermal stresses and to avoid resulting substrate bending, a key issue in obtaining large area 3C-SiC surfaces. +In summary, the almost universal use of Si has allowed significant progress in the understanding of heteroepitaxial growth of SiC on Si. +However, mismatches in the thermal expansion coefficient and the lattice parameter cause a considerably high concentration of various defects, which is responsible for structural and electrical qualities that are not not yet statisfactory. + +SiC on SiC epitaxy ... \section{Ion beam synthesis of cubic silicon carbide}