T. Arai et M. Tomitori, SCANNING AUGER-ELECTRON MICROSCOPY EVALUATION AND COMPOSITION CONTROLOF CANTILEVERS FOR ULTRAHIGH-VACUUM ATOMIC-FORCE MICROSCOPY, JPN J A P 1, 36(6B), 1997, pp. 3855-3859
Atomic force microscopy (AFM) tips have been evaluated on a submicrome
ter scale using a scanning Auger electron microscope (SAM) with a fiel
d emission electron gun. The commercially available AFM tips on the ca
ntilever as supplied were usually covered with carbon and oxide layers
as identified by the Auger spectra. A piezoresistive cantilever can b
e easily heated by passing a small current into the resistive film on
the lever. The carbon and oxide layers can be reduced by heating the c
antilever at temperatures higher than 700 degrees C and simultaneously
irradiating with an electron beam. However, the layer in which carbon
is strongly combined with the Si substrate cannot be completely remov
ed by the above method. The tip then was cleaned by Ar ion sputtering
and thermally oxidized to form a clean Si oxide layer. The oxide layer
was removed only by heating at 700 degrees C. Thus a clean Si tip can
be obtained in an ultrahigh vacuum (UHV) AFM chamber by heating the t
ip, which is then covered with clean Si oxide as a protective layer.