A NOVEL ZNO WHISKER TIP FOR ATOMIC FORCE MICROSCOPY

We have fabricated thin-film cantilevers with a zinc oxide (ZnO) whisker tip grown by vapor phase reaction for atomic force microscopy (AFM). The ZnO whiskers are tetrapodal structural single crystal. Each leg of the whiskers has high mechanical strength, high aspect ratio (cone half angle of 1-degree-2-degrees), a small radius of curvature less than 10 nm and a length of 5-30-mu-m. Manganese sulfide (MnS) films epitaxially grown on gallium arsenide (GaAs) substrates were employed for AFM imaging. The comparison between the AFM images using a ZnO whisker tip and a commercially produced Si3N4 pyramidal tip which had a side-wall slope of 55-degrees revealed that the former was able to resolve deeper and finer surface structures. This initial success suggests that ZnO whisker tips will be quite useful in topographic measurements of surfaces on which deep trenches or hillocks are microfabricated.