INTERSTITIAL DEFECTS ON (113) IN SI AND GE - LINE DEFECT CONFIGURATION INCORPORATED WITH A SELF-INTERSTITIAL ATOM CHAIN

Detailed structural data of the {113} interstitial defect or the rod-l ike defect in Si and Ge have been given based on firm experimental evi dence by high-resolution transmission electron microscopy (HRTEM). We have found line interstitial defect structures, in which a few chains of additional (interstitial) atoms in the [110] direction are inserted in a perfect crystal without dangling bonds in the {110} cross-sectio n. We have also found various kinds of atomic steps, whose ledges are parallel to the [110BAR] direction, in the extremely extended (113) pl anar defect. The HRTEM images of a bend of a {113} planar defect have been also presented. The interstitial defect structures mentioned abov e have been determined by HRTEM with image simulation. Based on the ex perimental evidence, we have shown that the observed structures such a s the extremely extended part on {113}, the bend, the steps and the di sturbed structure in which the hexagonal structure with stacking fault s exists have been consistently reproduced by successive nucleation of the line interstitial defect structure. In this context, we have conc luded that various disturbed structures are growth faults during devel oping of the planar {113} defect, rather than due to the formation of the hexagonal phase. We have shown transmission electron diffraction ( TED) patterns from a single (113) defect, and optical diffraction patt ern (Fourier transform) of a HRTEM image of a {113} defect. The TED pa tterns taken with various incident beam directions including the plan- view incidence have shown extra spots from the defect. The extinction of the extra spots has been also found in the pattern taken with the [ 001] incidence. The location of the extra spots and the extinction hav e been consistently explained based on the planar {113} defect model w hich was determined from the HRTEM observation before. Furthermore, el ectron diffraction intensity has been simulated based on the atomic mo del. Simulated electron diffraction has reproduced well the characteri stic intensity distribution from the defect. The reliability factor ha s been estimated in the plan view pattern to be 0.30. There has been l ess experimental information regarding self-interstitials in Si and Ge than vacancies and impurities. We emphasize that a series of our pape rs are the first elaborated transmission electron microscopy and diffr action studies combined with theoretical calculation that determine wi thout doubt the agglomerate structures of self-interstitial atoms in S i and Ge at atomic level.