Yh. Qian et al., ELECTRICAL AND OPTICAL CHARACTERIZATION OF EXTENDED DEFECTS IN SIMOX STRUCTURES, Semiconductor science and technology, 11(1), 1996, pp. 27-33
A novel electron beam induced current (EBIC) technique, which utilizes
two adjacent front contacts (one Schottky and one Ohmic), has been de
veloped to characterize electrically active extended defects in the si
licon overlayer of SIMOX structures. The results have been compared wi
th photoluminescence measurements on the same samples. EBIC measuremen
ts on n-type SIMOX layers show that dislocations and precipitates pres
ent in the overlayer act as recombination centres. PL spectra exhibit
dislocation-related emission, the intensity of which correlates with t
he change in density of extended defects measured by EBIC as the exper
iments are scanned across the wafer. P-type SIMOX material is found to
contain stacking fault tetrahedra and pyramidals at the upper silicon
-oxide interface and threading dislocations extending across the Si ov
erlayer, but the PL emission of these defects is negligible. Thinning
the overlayer by a sacrificial oxidation process creates oxidation-ind
uced stacking faults in the overlayer, which give rise to strong dislo
cation-related PL emission. It is demonstrated that electrically activ
e extended defects in the silicon overlayers of SIMOX structures are a
lso optically active, and that PL measurements can provide a valuable
insight into the electrical activity of the thin overlayers in these s
tructures.