A scanning electron microscope is used to scan the etched facet edge to produce digital data representative of its profile. A Fourier transform of the edge profile is produced and the resulting plurality of spatial frequency components can be used to generate a first low frequency waveform component indicative of lack of precise edge definition, a midrange frequency component indicative of poor liftoff samples, and a high frequency component indicative of metal grain size. A tilt adjustment feature of the electron microscope is optionally used to advantageously magnify the shape of the profile in the y direction.