The effects of substrate annealing on the growth morphology of bcc-Fe(001)
films epitaxially grown on MgO (001) surfaces have been investigated. Subst
rate annealing at 1000 degrees C for 30 minutes produced step-terrace surfa
ces which are the basis of flat and square Fe islands. By increasing the an
nealing time, the step profiles are improved to form long straight steps. L
onger annealing time caused an increase of segregated impurities regions an
d a reconstruction of the MgO surface. The presence of the segregated impur
ities and the reconstructed MgO surface negate the annealing effects, i.e.
it reduces the step edge growth that enhances the formation of round island
s, degrades the uniformity of Fe island size and increases the rms roughnes
s of Fe films.