The tunneling microscope is used to excite electron standing waves in
thin epitaxial layers of CoSi2/Si(111). We observe misfit dislocation
lines in topographic images that correlate with domain boundaries dete
cted in conductance images, indicating that they separate regions of d
ifferent cobalt disilicide thicknesses. These thickness transitions ar
e expected to occur at interface steps in association with the introdu
ction of partial dislocations for strain relief in this lattice mismat
ched system.