N. Braga et al., FORMATION OF CYLINDRICAL N-P JUNCTION DIODES BY ARSENIC ENHANCED DIFFUSION ALONG INTERFACIAL MISFIT DISLOCATIONS IN P-TYPE EPITAXIAL SI SI(GE)/, Applied physics letters, 64(11), 1994, pp. 1410-1412
Arsenic enhanced diffusion along individual misfit dislocations in Si/
Si(Ge) heterostructures has been detected and imaged using scanning el
ectron microscopy (SEM) and in the electron beam induced current (EBIC
) mode. The formation of buried cylindrical, or conical, diodes surrou
nding misfit dislocations has been observed. The diffusion enhancement
is not uniform for each dislocation. EBIC/SEM micrographs reveal a da
rk recombination contrast in the vicinity of the dislocation core and
a white generation signal within the space-charge region of the surrou
nding n/p diode. Based on an experimental isoconcentration etching pro
file and a simple model for enhanced diffusion, the dislocation diffus
ion coefficient for arsenic is estimated to be up to six orders of mag
nitude higher than that in the host crystal.