LOW THERMAL POWER ELECTRON-BEAM ANNEALING OF SCANNING TUNNELING MICROSCOPE TIPS

An add-on unit was developed that allows the cleaning of scanning tunn eling microscope tips by electron beam annealing even if they cannot b e disconnected from the piezo scanner in situ. The whole scanner tip c ombination, which is attached to a linear motion stage, is subjected t o a pulsed annealing treatment. The heat impact is focused on the oute rmost tip by sticking the tip through a hole in a grounded Mo screenin g plate with the cathode mounted on the apposite side. Tungsten tips a ttached to the scanner of the Omicron ultrahigh vacuum Multiscan Lab w ere annealed to achieve atomic resolution of ultrahigh vacuum cleaved GaAs (110) faces. A highly doped superlattice package grown on semi-in sulating GaAs was also able to be investigated on the cleaved (110) fa ce due to the ability of exact tip positioning with a scanning electro n microscope. (C) 1997 American Institute of Physics.