MAPPING 2-DIMENSIONAL ARSENIC DISTRIBUTIONS IN SILICON USING DOPANT-SELECTIVE CHEMICAL ETCHING TECHNIQUE

Transmission electron microscopy (TEM) image contrast was used to char acterize doping-dependent etching of n(+)/p junctions in silicon. The local variations in crystal thickness give rise to the appearance of t hickness fringes which may be interpreted as two-dimensional iso-conce ntration contours that map the dopant distribution. The etchant soluti on used for selective chemical etching of TEM samples prepared using w edge technique was modified to reduce the etch rate and maintain high selectivity to the n(+) doped region. The two-dimensional dopant profi les were quantified by calibrating against one-dimensional secondary i on mass spectroscopy data and also compared with one-dimensional sprea ding resistance analysis data. (C) 1997 American Institute of Physics.