It has been shown for the first time that the high-temperature anneali
ng of a diamond film in contact with Mn and Fe can reveal the microstr
uctural features within the film. The diamond film was annealed in con
tact with Mn and Fe at 900-1000 degrees C for 0.5-20 h. After annealin
g the sample was cleaned by acid and was rinsed in acetone. The cleane
d surface was observed by scanning electron microscopy under a seconda
ry electron mode. A clear image of the etch pattern appeared on the fl
attened diamond him surface from the reaction with the metals. The det
ailed microstructural features in the etch patterns were correlated to
those on the as-grown surface. The image contrast in the etch pattern
was related to the local defect density: the more defective region ap
peared darker. The origin of image contrast on the etched surface was
discussed.