DEVELOPMENT OF ULTRAHIGH-VACUUM ATOMIC-FORCE MICROSCOPY WITH FREQUENCY-MODULATION DETECTION AND ITS APPLICATION TO ELECTROSTATIC FORCE MEASUREMENT

We succeeded in high resolution force measurements by using a nonconta ct ultrahigh vacuum-atomic force microscope (UHV-AFM) with frequency m odulation (FM) detection. We clearly observed adatoms and corner holes on the Si(111)7 x 7 reconstructed surface. Then we applied the noncon tact UHV-AFM with FM detection to the high resolution measurement of t he electrostatic force. We prevented deterioration of the spatial reso lution of the topography by isolating the electrostatic interaction fr om van der Waals interaction. By simultaneous measurements of the topo graphy and electrostatic force on a silicon oxide, a spatial resolutio n similar to 15 Angstrom of the electrostatic force was achieved. (C) 1997 American Vacuum Society. [S0734-211X(97)10204-9].